- “This is going to be the best summer ever! We'll ride down every road, see the world together, it'll be amazing!”
- ―Luca in the Luca teaser trailer
Luca Paguro is the titular protagonist of the 2021 Disney•Pixar animated feature film, Luca. He is a sea monster that is influenced by Alberto Scorfano to venture into the surface. Once he discovers his parents will send him to the deep, away from the surface, he and Alberto escape to the Italian town of Portorosso, and enter the Portorosso Cup so they can buy a Vespa and see the world together.
- Luca Paguro is a bright and inventive 13-year-old sea monster with endless curiosity – especially when it comes to the mysterious world above the sea. Although he's been warned his whole life that the human world is a dangerous place, he longs for something beyond his quiet farm life where he herds goatfish day after day. So when another sea monster with actual experience above the surface takes Luca under his fin, his eyes open up to a whole world of possibilities.
Luca starts out as a very timid and shy but curious and imaginative character. He is afraid of the surface, but is also very curious about it. He meets Alberto, who Luca thinks is a human diver, but turns out to be like a sea monster just like him. After Alberto introduces him to the surface, Luca attempts to confidently refuse staying there as he believes himself to be a "good kid." When he receives the opportunity to approach the surface shortly later on, his first reaction is reluctance to disobey his parents' orders and see Alberto again.
As the movie progresses, Luca is able to expand on his curiosities about human life and what was on the surface as Alberto shows him his collection of human items. Alberto is able to teach Luca to ignore his doubts and leave his comfort zone, which is how he gained his skills on a bicycle that he needed to compete in the Portorosso Cup. He credits Alberto with teaching him how to be crazy.
Luca was also a very kind-hearted individual who was willing to stand up towards anyone who threatened to harm his friends. Luca also held a strong desire to see the world above the surface, despite being forbidden by his parents in doing so. Luca was very intrigued in learning new things, which he enjoyed doing while spending time in Portorosso and growing super excited when he learns something new.
He starts bonding with Giulia when she tells him about astronomy and the universe, which makes Luca want to go to school with her. After deeply hurting Alberto, Luca attempts to make it up to him by winning the prize money for their Vespa. He was even willing to come to Alberto's rescue and expose himself as a sea monster when Ercole caught and attempted to kill Alberto when his sea monster identity was revealed during the Portorosso Cup.
By the end of the movie, Luca is much braver and wiser than the fearful, nervous version of him that existed early in the story.
In human form, Luca is slender with fair skin, rosy cheeks, brown eyes, and wavy, dark brown hair. He wears a teal striped ivory button-down shirt with sleeves rolled up to his elbows, blue shorts, and is barefoot all the time.
In sea monster form, Luca has blue-green scales, sharp teeth, and blue "hair". His eyes are still brown, but they have bright yellow sclera and oval shaped pupils. He also has a long tail with smooth blue caudal fins. Before Luca obtains his new outfits, he is seen wearing green pants made of seaweed.
Luca was first seen rounding up his fish (which are used as sheep) up and going around his neighborhood, and his neighbors are getting a bit annoyed, as they make it clear he’s done this before. As he is headed over to the little circle ranch, he sees “land monster” stuff around there and grows fascinated with them. Although slightly put on edge at first, Luca begins examining the items. Just then, he hears the motor of a boat. He begins ushering his fish under a rock that caves in. However, Luca stares up and imagines himself swimming closer. His fantasy ends when his mother calls him for lunch. Luca hides the human things, rounds up his fish and turns to go home. His mother, Daniela, begins to ask him if he saw a boat, pointing out that he’s two minutes late. Daniela begins explaining to Luca that the humans should never see him because they will kill him if they do. Daniela leads Luca in. During lunch however, Luca’s mind is somewhere else. His grandmother notices and asks Luca what’s on mind. Luca gets startled and begins asking where boats come from. With no hesitation, his grandmother tells him “from the Land Monster Town.” Luca begins excitedly asking his grandma questions, to the point where his mom has him stop his curiosity, telling him that the curious fish are the ones who get caught. She further tells Luca that they don’t discuss or go anywhere near the surface. Daniela hands a fruit over to Luca and tells him it’s time to get back to work. They head out where his mom reminds him that she loves him. Luca swims off.
Secretly, Luca begins looking for more human things and finds a wrench, and a cup that he uses as a telescope, where he sees a gramophone. Mesmerized, Luca begins examining it, not realizing that a diver is standing behind him, harpoon in hand. Luca eventually notices and screams. The figure corners him but when he gets cornered, Luca realizes it is just a sea monster boy named Alberto Scorfano, who decided to prank him. As Alberto begins getting his things together, Luca asks him if he lives around. Alberto responds with no and that he was only getting his things. Instead of grabbing his harpoon, he grabs Luca’s shepherd staff. Luca notices and follows Alberto, telling him he forgot his harpoon. Alberto thanks Luca and swims backward toward the surface. Luca asks what he’s doing and is confused when he sees Alberto’s human form. Alberto then grabs Luca with his staff and pulls him out of the water unto the surface. Luca becomes a human and begins screaming hysterically, while Alberto just watches. Alberto breaks this by asking Luca if it was his first time. Luca, panicked, says yes, explaining that he’s a good kid. Alberto tells Luca to relax and breathe. Luca does so and looks up. He sees the ocean water crashing gently on the shore, the trees bristling in the breeze and birds flying high in the clouds of the sky. Luca is marveled. Alberto then asks if it isn’t great. Luca says no, wishes Alberto a good day and leaves. Alberto then hands out Luca’s shepherd staff over the water. Luca grabs it, wishes Alberto a good day yet again and leaves for real that time. Luca lays in bed that night, wondering about what in the world just happened. Luca then tries to ask his grandma if she really has been to the surface. She only snores in response.
Come the next day, Luca sets up a decoy named “Smucca” proclaiming him as in charge and leaves to the shoreline. He repeatedly tries to come out of the water but fails numerous times. Alberto lets out a blasé “wow,” as Luca yelps, startled. Alberto then explains that it “was hard to watch.” Alberto swims up to the surface as Luca follows. Luca watches Alberto dry off and go into his human form. Luca tries to walk up holding Alberto’s object he handed him but falls. Luca watches, amazed, as he turns into a human himself. Luca gets confused, as he says he feels his tail is still there, with Alberto explaining that it’s called a “phantom tail” and that he will get used to it. Luca tries to get up to walk, but falls and begins jumping around like a half dead fish. Alberto then remembers that walking is the first step of seeing the surface in full. Alberto begins trying to teach Luca to walk, proclaiming that he “basically invented it.” Alberto teaches Luca that walking is like swimming, only with no tail and there no water, otherwise, it’s just the same thing. Luca tries but falls. Alberto says to try again and to try leading with his head. Luca tries, as Alberto tries to tell him to use his belly a bit more. Luca tries but falls backwards. Alberto tries to have Luca not think about it. Luca is confused, as he says he can’t not think about doing something. Alberto groans and shows him that he just has to lean and catch himself before he falls. Luca watches Alberto walk around for a bit. Alberto then pushes Luca to get him to try to catch himself with his legs. Luca does and begins to walk around, with Alberto saying that it wasn’t bad. He introduces himself as Alberto Scorfano and Luca introduces himself as Luca Paguro with a handshake. Alberto says something in Italian, a type of greeting and says that it’s a human thing, saying that he’s an expert when it comes to humans. Luca asks what that means but Alberto doesn’t necessarily have an answer. To distract Luca from his question, Alberto takes Luca to his tower.
The pair make it and Luca is amazed. He asks if Alberto lives there and Alberto responds that he and his dad live there but his dad isn’t around a lot so he just does whatever he wants. Luca asks if it is dangerous, with Alberto promptly saying yes and that it’s the best, adding in that everything good is above the surface. Luca asks in what ways. Alberto examples a couple of things, such as air, gravity (or falling) the sky, the clouds and the sun. To top it all off, Alberto says that there’s also human things. The pair climb up the tower via a ladder that has been repaired by Alberto. Luca climbs up first and notices all the items. Alberto tells Luca to feel free to ask anything as he has been collecting for quite a while. Luca comes next to the gramophone, with Alberto stating that it’s “the magic singing lady machine” but that it’s broken. Luca fixes it, with Alberto excitedly declaring so. Luca’s eyes then land on a Vespa poster. Luca asks what it is and Alberto explains what it is, saying that it’s the best thing humans have ever invented. He further explains that it take you wherever you want to go “in the whole stinking world.” After Luca’s short daydream of riding a Vespa, he notices Alberto has all of the parts to make one. He tells Alberto this, with Alberto realizing so and excitedly declaring that they’re going to make one. Luca then says he has to leave with Alberto asking if he has to that second. Luca explains that it will be bad for him if he doesn’t return. Luca says goodbye to his new friend but, ultimately, ends up helping Alberto make a DIY Vespa until around sunset. Luca keeps telling goodbye to Alberto throughout the whole process, with Alberto saying “bye” or “see ya” whenever he does. When they finish the Vespa, Luca leaves and Alberto says that he’ll see him tomorrow.
Luca makes it home late. His mother asks him where he’s been. Luca has a short nightmare of him telling his parents he was at the surface and his foot was still human. Luca tries to excuse himself, but his grandma covers for him, telling Daniela that she sent him out to look for sea cucumbers. Luca plays along, fake apologizing to his grandma. Luca thanks his grandmother in a whisper and goes to bed giggling, happy to have seen the surface.
Come the next day, Luca returns to Alberto again. Luca sees that Alberto got the Vespa down. He explains that he rode it down, but he actually threw it out the back window. Alberto states that it took a while to repair but it works perfectly fine now. Alberto wants Luca to ride it with him but Luca refuses, scared of the idea as he looks exactly where Alberto plans to go, which is over a ledge of the island. Luca further explains that he feels like that he would probably die if he tried. Alberto than asks Luca to hold the ramp for him instead, since he doesn’t want to ride the Vespa. Luca is scared holding the ramp and asks Alberto if they “can sleep on it.” Alberto reassures Luca, telling him not to move no matter what. Alberto releases his grip on the ground and let’s the Vespa take control. However, it begins breaking apart as he descends down the cliff. He tries to halt using his bare foot, but clenches it back as the impact hurt. Eventually, the last part of the Vespa, the spot Alberto is sitting on breaks. Sending him flying, Alberto catches himself with his legs and begins running, unable to stop. Luca gets even more nervous, as Alberto begins yelling at Luca not to move, running up the ramp and falling into the ocean. Alberto lays face down in the water, the water having transformed him back into a sea monster. At first, Luca thought he killed him and begins panicking. Alberto then turns around whooping and cheering, screaming with exhilaration that it was fun. Luca asks if it was really fun, with Alberto saying that it really was, asking if Luca saw the height he got to. Alberto shakes himself dry. He then says that Luca did good ramping for him. Alberto then tells Luca that they should make another one. Luca gladly helps.
The two friends begin making a new Vespa. Alberto also hands over some human clothes to Luca during their time together. They also dance around to Italian music. They decide to test the new Vespa, with Luca holding the ramp again, but due to the lack of steering controls, Alberto instead lands face first on the ramp. Luca is worried that Alberto might have hurt himself but Alberto is just happy he made it down the cliff. Alberto shows Luca new things, like jumping off ledges into the ocean below. Luca doesn’t do well, instead belly flopping with Alberto laughing. Luca also makes his own Vespa poster, with Alberto looking at it nicely, while scratching his back with a clothes hanger. Luca gets an idea with it and adds it onto the Vespa, which allows it to steer. The two also spy on fishermen boats, where they learn new Italian sayings of the worst variety. They both hang out at the shoreline. Luca messes around with two snails and fixes his hair with their slime to look like Alberto’s. They stare off into the sunset, with hands over each other’s shoulders.
It is morning once again. Luca is back with Alberto. Alberto asks Luca if he’s ready to ride. Luca asks who’s holding the ramp, which is actually a turtle. Alberto tells him that he’s faster than he looks and to hurry. Luca tells Alberto that he’s too scared. Alberto apparently knows his problem, explaining that he has a “Bruno” in his head, something he says is a voice that tells you the negative side of things, explaining how he gets one too sometimes telling him that he can’t, that he’s gonna die and not to put things in his mouth. Alberto teaches that to stop it, he has to say “Silenzio, Bruno!” Luca repeats but Alberto says to say it louder. They do this two more times. Alberto than asks if he can still hear it, with Luca responding no and he only hears Alberto. Alberto throws a “helmet” over Luca’s head (which is actually a metal pasta skimmer) and they begin their descent down the cliff. Alberto whoops and hollers. Meanwhile, the Vespa breaks in half, but Luca holds onto Alberto for dear life and to keep it together. Luca repeats “Silenzio, Bruno!” over and over as they go down and eventually make it over the ramp. They both look at seagulls in awe but then realize they’re falling and are going to hit a giant rock. Luca pushes himself off of Alberto to split the Vespa in half to avoid hitting it. They both fall in the water. They both begin cheering, with Luca falling backward in the water laughing happily.
It is now nighttime. Luca questions the stars in the sky. Alberto explains that they’re actually anchovies and they go to sleep up there with the big fish (the moon) to protect them. Alberto says that he touched it once and it felt like a fish. Luca is wowed. Luca sits up and looks at the town not too far away. He asks Alberto if he’s ever been there. Alberto says yes, but quickly says no. He explains that his dad has been there before and has told him everything so he is an expert. Luca says that Alberto is lucky, his dad letting him do whatever he pleases, with Alberto agreeing. Alberto notices Luca is let down. To lift his spirits up, Alberto begins explaining when they almost hit the rock earlier. The boys laugh. Luca then states to Alberto how amazing it would be to own a real Vespa: Alberto says that it’s the dream. Luca has a dream about riding through a prairie on a Vespa and shooting into the sky to touch the fish. However his dream ends scarily, with him falling. Luca jolts awake, but Alberto is fast asleep. Luca begins panicking, as he realizes he fell asleep. His startlement wakes Alberto up. Alberto only leans up and asks what is happening and falls back asleep in no time.
Luca goes back home, relived he got away with it, only for his mother to clear her throat, arms folded at Luca. She sits him down on the table, with the human things he found on it. His father, Lorenzo, explains to Luca that he’s in big trouble, making him promise to never sneak off to the surface again. Luca defends himself, saying that it’s not so bad saying that he and his new best friend, Alberto are always careful. His Uncle Ugo pops up, with Luca’s father introducing him. Ugo begins explaining what an honor it is to meet him at last but stops mid sentence because of a heart attack. Lorenzo has Luca punch his heart and after Luca does so, Ugo explains that there’s no light in the deep but there’s nothing to see anyways. He then tells Luca that there’s no time to lose. Luca, frightened, asks his mom what he’s talking about. Daniela explains that they plan to make him live in the deep with his Uncle Ugo, for the rest of the season. Luca tries to defend himself again, and Daniela makes it two seasons and threatens Luca that she’ll make him stay for three. Luca asks why she’s doing this, with Daniela saying that the world is dangerous and that she’ll do anything to keep him safe. Luca, now mad, tells her she doesn’t know what it’s like on the surface. Daniela then tells Luca that she knows him and what is best for him. Luca looks down with a look of complete discontent on his face. Daniela tries to remind Luca she loves him, but Luca angrily grunts and swims off. Luca thinks about what just happened. Luca finally decides what he’ll do and sneaks out to find Alberto.
Luca explains his situation to Alberto. Alberto offers Luca to stay but Luca says his family will look for him. Alberto says that it might be true and looks out the window. He then smiles and asks Luca if they will look for him over there, pointing to the town not so far away. Luca asks if they’ll survive, Alberto replying that they can do anything. He goes to explain that they’ll “swim right over to Vespa Town,” and “track down Signor Vespa.” Luca is intrigued and Alberto shows him a drawing he made of a Vespa. Alberto then tells Luca to think about it, everyday they will ride somewhere new and every night they’ll sleep under the “fish” (stars) with no one to tell them what to do, just he and Luca out in the world, and free.
Alberto jumps off a cliff into the ocean. Luca is scared, but as he looks off to the town, he repeats “Silenzio, Bruno!” and jumps into the sea. The two boys begin swimming. Luca tries to avoid a rock but Alberto grabs his arm and pulls him out to jump over the rock. Luca doesn’t land as gracefully as Alberto. Luca instead bellyflops and Alberto laughs. Alberto then gains speed and leaps out of the water, with Luca trying to copy him and failing. Then he gets the hang of it and the two begin jumping in and out of the water, whooping with joy. The two laugh and swim to the coast of Portorosso.
Luca and Alberto arrive at the Portorosso bay. They stare in awe at the little town. They hear a boat motor and immediately dive into the water in a panic. A girl questions her dad what those things are, as Alberto and Luca swim to the bottom of the water. They hide behind a sunken fisher boat. Luca questions how they’ll get up into land without being seen. They both look down at the boat and smile. They use the boat to get out of the water and dry off underneath it. Luca and Alberto make their way into town. Alberto assured Luca that it will be a breeze reminding him not to get wet under no circumstances. Luca begins rethinking his decision to go when he sees fishermen with dead fish on a hook and a harpoon in one of the fishermen’s hand. Luca tells Alberto that the town seemed crowded and turns to go back, but Alberto drags Luca from the collar of his shirt, reminding him of “Silenzio, Bruno!”. Luca slaps his hands over his face as Alberto says the Italian saying to the fishermen, making them gasp. Luca excitedly states that it worked. Alberto then tells Luca to just follow his lead.
When Luca sees the plaza of Portorosso for the first time, he is amazed at the beautiful sights. Alberto asks Luca if it isn’t cool. Alberto then tells Luca to say the thing they learned. Luca does so to two old ladies, who gasp and hit the boys on their heads with their umbrella and purse. They also stick their ice cream in their hair. Alberto licks his as Luca states that maybe he said the thing wrong. Alberto then shoves the ice cream that was in Luca’s hair into his mouth. Luca loves it and savors the sweet flavor as he notices something. He realizes that there are portraits of fishermen killing sea monsters and begins getting scared. Luca drops his ice cream and tells Alberto that’s it’s time to leave, stating it’s too dangerous. They both are interrupted by Ercole, who is riding his Vespa. They stare but as Ercole comes near, he nearly crashes into them. Luca stealthily pulls Alberto out of the way. They stare at the Vespa and begin walking over. Just then, some kids playing kickball on the plaza lose their ball. It rolls over to Luca, where one of the kids asks him to kick it. Luca doesn’t know how and kicks the ball wrong. As a result, the ball hits Ercole’s Vespa. Ercole asks who got lucky, while everyone points at Luca and Alberto. He begins pestering the boys. Ercole goes to tell Luca that he stank like fish and drags him to the water fountain, with Alberto being held off by Ciccio and Guido. Ercole doesn’t manage to dunk Luca in the fountain, but little droplets touch his cheek, making it begin to transform. Just then, a girl named Giulia rushes over on her bike and stops Ercole, as Luca wipes the water off his cheek. She has Luca and Alberto board her wagon and leaves with the boys.
Giulia begins explaining that “underdogs” need to look out for each other. Alberto confused, asks what is “under the dogs.” Giulia corrects Alberto, explaining that “underdogs” are kids who are different; dressed weird and sweatier than usual. She lifts up her arms and shows her shirt stained with armpit sweat. Luca groans. Alberto just stares. Giulia awkwardly shakes it off, asking Luca and Alberto if they’re in town for the Portorosso Cup. The boys don’t answer. Giulia ends the conversation with the fact that she had to go deliver fish. Luca and Alberto hop off the wagon. Luca realizes that Ercole talked about being able to pay for a Vespa through racing and winning the Portorosso Cup. Luca has Alberto ask Giulia for details. Although reluctant, Alberto goes on to ask Giulia what they get for “racing in a cup.” Giulia stated that they would win prize money for winning the race. Alberto turns to walk away, but Luca turns him around and has him keep going. Luca has Alberto ask if the money can be turned into something else. When Giulia asks as to what, Luca points at a Vespa. Giulia says no but could get them something else and points at a nearly broken down and rusted Vespa. To Luca and Alberto, it’s beyond perfect for them. Alberto states that they’ll just win the race and beat Ercole. Giulia explains that it isn’t just a race and that it’s a triathlon, which included swimming, cycling and eating pasta, further adding that they would need a teammate to make it through the race. Alberto tells Giulia they’ll figure it out and thanks her. Luca then grabs Alberto’s shoulder and tells him that Giulia could be on their team. Alberto is on board for the idea and gladly proclaims to Giulia that she’s part of the team. Giulia rejects the offer, stating she raced alone. Luca then says that they could be “under the dogs” together. Giulia then has Luca show her if he can bike. Luca obviously can’t, jumping on the bike and falling repeatedly, while Alberto frustratingly tries to coach him through. Giulia tells Luca to look up and he won’t fall. Luca does so and rides around the plaza. Giulia then tests Luca to see if he can dodge obstacles, withstand passive-aggressive verbal assault and make it over the fountain without falling. Luca however, falls off the fountain, Alberto rushing over to help. Giulia asks Alberto if he can swim at least. Alberto begins explaining that he’s amazing but is stopped mid sentence by Luca elbowing him, as to not blow their cover. Giulia is extremely confused as to how Luca and Alberto don’t know how to bike and swim. When Giulia asks where they’re from, Alberto is unwilling to tell her but immediately after says that he and Luca are runaways. Luca explains further that his parents were going to send him away and if he and Alberto can win the race, they’ll be free. Giulia gets slightly unsure but accepts and tells Luca that he’ll bike, Alberto will eat, and Giulia will swim. The trio put their hands together, naming their team “The Underdogs.”
Giulia invites Luca and Alberto to dinner at her house. That’s where Luca and Alberto meet Massimo, Giulia’s intimidating, fisherman father. Luca and Alberto get frightened when they see harpoons on the wall. Alberto asks Luca what he thinks Massimo kills with the harpoons. Massimo responds that he kills “anything that swims,” while chopping the head off of a fish. Luca chuckles nervously, as Alberto just stares in horror. Massimo then hands Giulia a newspaper, showing a picture of a supposed sea monster sighting. Giulia scoffs saying that “everyone in Portorosso pretends to believe in sea monsters.” She shows Luca and Alberto the photo. Alberto lightly chuckles but Luca just looks, nervous. Massimo then proclaims that he’s not pretending, while grabbing the picture and stabbing it on a board with a knife. Luca gets so nervous that he spits water on Alberto, causing half of his face to transform. Luca yelps as he drags Alberto under the table. He manages to wipe off Alberto’s face, but Giulia’s cat, Machiavelli, sees Alberto’s true form and grows suspicious of the boys. Luca says that they slipped, while smiling awkwardly. Luca and Alberto let out a sigh of relief. Massimo then hands the kids pasta. Luca picks up a fork, not knowing how to use it. He chuckles anxiously and gulps. Alberto then begins eating with his hands. Luca follows Alberto’s approach and tastes the pasta with his hands. When he realizes how great it takes, he begins eating messily, as Giulia just watches. When Massimo asks where the boys are from, Giulia states that they’re classmates, Luca and Alberto, who came for the race. Massimo talks to Giulia, not wanting her to enter the race due to past experiences and their shortage of money. On the fly, Luca offers that he and Alberto can help, with Alberto stating that they know lots of fish. Massimo accepts and Giulia hugs her father. Machiavelli attacks Luca and Alberto shortly after. Giulia leads them outside and let’s them stay in her treehouse. After bidding them goodnight, Luca reminisces how he rode the bike after taking Giulia’s advice. Alberto says that once they win the race, they will be out of the town. Luca agrees and deeply sighs, happy. The boys eventually fall asleep under the stars.
The next morning, Luca wakes up and finds out that he and Alberto reverted to their sea monster forms due to it raining the previous night. Luca wakes Alberto up and they panic as Giulia begins pretend-playing the wake up theme from the military. Luca and Alberto try to make a run for it, but Massimo gets in the way. They stumble and, behind the tree, they manage to dry off. Massimo has Giulia do the fish deliveries and has Luca and Alberto come with him to go fishing. Luca and Alberto wear pairs of gloves and boots, to avoid their hands and feet getting splashed by water and transforming in front of Massimo. A fisherman greets Massimo and tells him to look out for sea monsters. Massimo comforts the fisherman, telling him that his eyes were peeled and that they wouldn’t get away, while pulling Out a harpoon. Luca laughs nervously. A sudden bump in the boat causes Luca’s forearm to get splashed and partially transform. He hides this behind his back. As Massimo walks back and forth in the boat, Luca and Alberto slide back and forth on the boat. Luca nearly falls in on two instances. Both of the these instances were adverted by Alberto, by him either stiffening up or grabbing Luca’s arm. The boys begin pulling the nets in. Luca gets nervous as Machiavelli grumbles at him. Machiavelli eventually attacks Luca. Luca manages to pry him off but Machiavelli lands in the sea. When Machiavelli is back in the boat, Luca gives him a small fish to content him for a short while and to avoid being attacked again. Luca eventually learns that Massimo was born with one arm, and sees just how well he does with it. Massimo is disappointed by their catch, with Luca explaining that they were over a haunted fish graveyard. Alberto then explains that the fish said so and that they knew it wasn’t. Alberto eventually points where the fish are. They all come back with a huge stack of fish. Luca greets Giulia as she stares in amazement. Massimo then points out that they really knew fish. Excited, Giulia has Luca and Alberto follow her to sign up.
The kids make it to the sign up register. There, they are greeted by Signora Marssegliese, who is doing an advertising skit about Giorgio Giorgioni, slayer of sea monsters and “beloved purveyor of pasta.” Luca gets a little worried, but Giulia explains that it’s just pretend and that it’s Signora Marssegliese, who sponsors the Portorosso Cup. Giulia grudgingly adds in that it was gonna take forever. Giulia then has her get to the rules. Signora Marssegliese begins explaining everything that will go down in the race. At the end of the explanation, Luca states that it sounds hard. Alberto assures Luca that they will win, just as Ercole walks in. Ercole pesters and steals Giulia’s money for their entry fee. After some more pestering, Ercole slaps Alberto’s nose with a sandwich, which angers him and prompts him to fight. Luca says Alberto’s name, signaling him to not do it. Alberto tells Luca that it’s for their Vespa. Ercole laughs as Giulia says that he’s just scared “they’ll end [his] evil empire of injustice.” Ercole asks Giulia if she has a new insult, where Luca tells her to call him a “catfish” when she begins stuttering. When everyone is obviously confused, Luca explains that “they’re bottom feeders and they also have two sad little whiskers.” Ercole gasps and has Luca listen. Ercole tells Luca that he eats kids like him “for breakfast.” Luca gulps, nervous. Ercole then prompts Luca to sign up, while handing him back the money they made, telling him that destroying their team will be his priority. Giulia is proud of Luca and once Ercole leaves, Luca Giulia and Alberto sign up.
Giulia begins training Alberto, with Luca balancing and handing over plates full of pasta. Giulia then trains Luca. Luca is trained first going uphill on his bike. However, Luca is pretty slow, which makes Alberto slap his hands on his face and groan in disappointment. When they reach the top of Portorosso, Luca looks down and is scared to go down. Ercole is there too and pesters Luca. Giulia tells him to go along and not to mind what Ercole said. Luca repeats “Silenzio, Bruno!” and tries to go down, but halts the bike and is sent flying, hitting the ground.
Giulia begins training her swimming. Luca asks Alberto if that was how humans swam, with Alberto shuddering, proclaiming that the way humans swim is embarrassing. Ercole is on the bay as well with Ciccio and Guido, all with harpoons to find a sea monster. He spots Luca and Alberto and decides to ram his boat into theirs. Giulia warns Luca and Alberto and tells them to get away as she begins swimming away herself. Luca and Alberto begin to try to paddle away but the boat only spins around and doesn’t move. Luca groans as he realizes that the boat is getting closers. He clenches his teeth in fear. At the last minute, Guido shifts the boat as to not ram into them. In the process, Luca manages to duck but Alberto is splashed by a wave, transforming him into a sea monster. Alberto yelps and quickly ducks down. Luca looks at Alberto, eyes wide as saucers and Alberto looks at Luca. While Giulia distracts Ercole, asking what is wrong with him, Luca looks around for something to dry off Alberto. He then spots that Giulia brought a towel tries to grab it to dry Alberto. However, while grabbing it, Luca accidentally elbows Alberto. He grunts and falls backward into the water. Luca looks overboard and gasps. He turns around to see that Ercole got suspicious and asks where “the other one” went. Alberto is hiding on the other side of the boat. Ercole looks at Luca, with a face full of fear. But when he looks down, Ercole notices Alberto’s tail underneath the boat. Ercole questions in Italian, confused as ever. Giulia begins shaking Ercole’s boat and makes him drop his wool sweater. As they’re distracted, Luca helps Alberto get in the boat again. At the very last second, Luca throws the towel over Alberto, just as Giulia gets in. He is back in his human form shortly afterward. Luca and Alberto grab their paddles and paddle away.
Later on, the kids return to Giulia’s house, but as they’re entering the gate door, Luca stops dead in his tracks and turns when he hears someone imitating a dolphin call. Luca stares as he realizes that his parents were in town, looking for him. Luca clenches his teeth and hides behind the gate door. He closes it. Later that night, up in the treehouse, Luca tells Alberto that he thinks he saw his parents. Alberto tells Luca that his parents weren’t there. Giulia then hops up and begins telling the boys about technique. Massimo leaves with Alberto, to help him draw in the lines. Alberto leaves as Giulia begins explaining that she was only there for the summer and the rest of the year, she lived with her mother in Genova to attend school. Giulia sadly states that everyone thinks of her as the weird kid who doesn’t belong. Luca agrees with her, hinting at the fact that he is “a weird kid” himself for being a sea monster that will probably never belong. Giulia asks why Luca wants a Vespa. Luca explains that he and Alberto will see the world and sleep under the “fish” every night. When Luca asks what she will do when they win, Giulia begins explaining that she’ll rub it in everyone’s face and say “I told you so,” further adding that Ercole’s life will be ruined. She apologizes to Luca for going overboard, but Luca tells her that it’s not too much for him. Giulia then tells Luca that they aren’t fish. Luca disagrees, saying that Alberto had told him. Giulia then has Luca follow her.
Luca and Giulia walk on the roofs of houses in the moonlight. Eventually, she makes it to a house with a telescope, stating that the owner lets her use it. Giulia has Luca look through the telescope. She asks if he sees fish. When Luca asks what they are, Giulia explains that they are stars, “raging balls of fire.” Luca looks down, stating that Alberto was wrong then. Giulia then shows Luca Saturn through the telescope. Luca has a daydream where he’s running on the rings of Saturn that is floating over an ocean. Giulia has Luca ride Leonardo Da Vinci’s flying machine. Luca hops on and they glide through the air. They fly through the Colosseum. Giulia then points down to Pinocchio and the fox and cat. Back in Giulia’s house, Luca has many questions, where Giulia explains. Luca tells Giulia to promise to tell him everything she says, practically yelling from excitement. Luca apologizes to Giulia, and Giulia tells Luca that it’ll never be too much for her. The two laugh as Alberto tells Luca it’s time to go. Luca asks if he can borrow Giulia’s astronomy book for the night. Instead, Giulia gifts him the book, crossing out her name and writing his. Luca thanks Giulia as Alberto again calls Luca. Alberto leaves, frustrated.
Alberto says he wants to show Luca something. Luca begins explaining that the "fish" are actually stars. Alberto disagrees with Luca, saying that they weren’t what he says. Alberto leads Luca to the place where they keep the Vespa they plan getting. They both stare in awe at the Vespa, as Alberto pulls out his Vespa drawing, only with more things added to it like gelato, pasta and an umbrella. Luca says that they should add a telescope, with Alberto saying that it should be one that shoots lightning. Luca disagrees and goes on to explain that Giulia has a bigger one at her school, as Alberto just stares at him. Luca then proposes that they should visit Giulia at her school and maybe even attend, expressing his curiosity about it. Alberto then explains that they're getting a Vespa to live on their own and asks Luca what he thinks will happen when people find out he is a sea monster. Luca looks down, sadly, as he realizes that Alberto is right. Ercole then throws a harpoon at the wall shows up out of the dark, mocking the boys that Giulia wasn’t there to keep them safe. Luca grabs Alberto’s arm, nudging him to leave. Alberto instead steps Luca behind him as Ercole comments that somethings fishy about the boys and that he wasn’t talking about their smell, but the fact that they’re hiding something Alberto tries to come up with an excuse to leave. Ercole has Ciccio and Guido grab Alberto. Luca tells Ercole to leave Alberto alone, but Ercole pushes him to the ground. Ercole then displays his discontent for the boys and proceeds to punch Alberto in the stomach, making Alberto wince in pain and cough. Luca then picks up the harpoon and shakily holds it toward Ercole, threatening him to stop, obviously afraid. Ercole tells Luca to put the harpoon down, pointing out that he’ll hurt himself: Eventually, Alberto breaks Ciccio and Guido's grip and stares at Ercole coldly as he tells both of the boys to leave. Luca drops the harpoon and grabs Alberto’s shoulder once again. They run right back to Giulia's house. Luca questions Alberto why he angered Ercole. Alberto shrugs it off, saying that he had it under control, reminding Luca that he had to follow his lead, while opening the gate door with force. Luca stares at Alberto. He steps in and closes the door.
The next morning, the training for the race intensifies. Luca begins taking over for Giulia and delivers fish to train. He does a quick perimeter check and makes sure his parents aren’t around. Then, Luca pedals and begins going to deliver the fish. As the days pass, Luca gets better and begins biking faster.
The next morning, Luca and Alberto are so tired they can't even walk straight. Giulia introduces them to espresso coffee. They both only stick their tongues in the mugs and groan. The coffee jumpstarts them, with Luca doing cycling with his legs. Luca’s biking has improved a huge amount, as kids cheer him on. Later that night at dinner, Alberto has trouble eating pasta with a fork. When Massimo shows him how and Alberto tries and succeeds, he wants to show Luca his accomplishment, but Luca is busy reading a zoology book with Giulia. Filling up with jealousy, Alberto angrily eats the pasta on his fork.
The next day, as Giulia trains Luca for his part in the race with cycling, they have a brief run in with his parents. Giulia and Alberto sit on the back of the bike. Luca, to avoid his parents, takes a different path. The trio make it to the top of Portorosso. Giulia notices the train and explains it takes her to Genova, with Luca asking if it goes to her school. Alberto says nothing, scoffing at the question. Alberto then redirects Luca's attention to the race, proclaiming they won't go anywhere if they don't win. Luca is scared but when Giulia tries to coach him on how to go down the hill, Alberto tells her to stop bossing him around, saying that he knows what he needs since he's his friend. Then Alberto takes charge of the bike, saying that Luca needs him and begins cascading down the hill at a dangerous speed. Luca keeps pleading Alberto to halt the bike, but Alberto refuses, making Luca think that it's "Bruno" telling him that. The two race down the hill. Luca and Alberto scream as they hit a metal gate. Luca and Alberto plunge into the ocean. Giulia catches up and begins calling for Alberto and Luca, afraid of what could've happened to them. Meanwhile, underwater, Luca and Alberto, back in their sea monster forms, hide behind two big rocks to avoid being seen by her. Luca then tells Alberto to leave before she sees them. Alberto follows Luca.
Luca and Alberto wash up on shore. Luca is obviously discontent, as Alberto begins explaining that he was showing him how to do it the correct way. Luca says that Alberto doesn't know how to do it the right way and all he did was crash them into the ocean, while shaking himself dry. Alberto reassures Luca, telling him everything is fine. Luca, panicked, begins explaining that his parents saw him. Alberto tells Luca that his parents aren’t around and that the town was starting to make him crazy. Alberto goes on to tell Luca that they just need the Vespa and they be out of the town, while putting his hand on Luca’s shoulder. Luca slaps his hand away and tells Alberto that it won’t be any different. Luca then tells Alberto what he really wants; he wants to go to school like Giulia. Alberto is shocked and resists but Luca says that he's just too afraid. Alberto tells Luca that he’s never afraid and that Luca is the one who always gets afraid. Alberto shoves Luca. Luca tells Alberto to shut up and the two get into a fight. Luca yelps when Alberto bites his hand. Alberto begins pounding him on the ground, asking him what will happen when Giulia or anyone sees him. Luca screams at Alberto to get off of him. Just as Alberto is ready to punch Luca, Giulia approaches them, happy they're safe and hugs them both.
However, Alberto and Luca exchange angry looks at each other behind Giulia’s back. When they break off, Luca and Alberto don't look at each other since they're still mad at each other. Giulia notices something is wrong, so she playfully scratches Alberto's head, but he growls at her. Luca then asks Giulia if they can go to school with her. Giulia is delighted as Luca says the greeting Alberto taught him. Alberto, out of a fit of jealousy and anger decides to take matters into his own hands. Alberto casually brings up the question if Giulia's school accepts everyone, even to those that aren't human. Luca notices was Alberto is after and says his name, signaling him to stop. Alberto doesn't and further asks if some students were sea monsters and states that he doubts the school would accept sea monsters. Luca stops Alberto and says that it was a very good "joke." Alberto says that it is very hard to imagine, so he'll just show them. Luca screams “No!” as Alberto dives into the water. Luca clenches his teeth in fear. Giulia approaches Alberto, not phased by his stunt.
Luca, panicked, tells Giulia to wait. Giulia comes near Alberto, who is face down in the water. Giulia tells him to quit goofing around as she grabs his arm. As she does, she notices that Alberto's arm is different, periwinkle and scaled like a fish. Giulia screams and backs up, whimpering. Luca watches the whole thing as Alberto rises up from the water, menacingly, crouched with claws ready to attack, fully transformed into his true sea monster self. He stares angrily at Luca and Giulia, as Giulia screams for help and pleads for him not to hurt them. Luca looks at Alberto with complete fear. Alberto tells Luca to see, telling him that he knew that this scenario would happen. Luca, unwilling to give himself up, yells "sea monster" while pointing at Alberto. Alberto gasps and says Luca's name, sadly. Luca looks at Alberto sadly, as Giulia then grabs a stick and points it at Alberto, telling him to stay back. Alberto backs up as Ercole, Ciccio and Guido run towards the shoreline with harpoons. That's when Alberto retreats into the water. Ercole and his boys throw their harpoons, wanting to capture and kill Alberto for the reward. Luca screams “No!” and watches, horrified, as each of the harpoons all miss Alberto. Alberto, however, does nothing to evade the harpoons. He sadly turns around one last time to see Luca. Heartbroken and betrayed, Alberto disappears in a wave. Luca stares off, hands over his mouth, as Ercole gets mad at both he and Giulia for letting the sea monster get away. Ercole and his friends then proceed to go find and kill Alberto while he was still near. Luca has no reaction, just staring off at where Alberto could’ve gone.
Later on, Luca and Giulia return to Giulia's house. Luca and Giulia are silent, lost in their thoughts as to what had just happened. Massimo then tells the kids that he was awaiting them and announces that he made their favorite pasta. Just at that moment, Massimo notices that Alberto isn't around. Luca explains that he left. Massimo asks if Luca has any idea where he could’ve gone, but Luca doesn’t know, adding in that Alberto probably doesn't want to be looked for. Worried about the boy's safety, Massimo sets out to find Alberto. A bit later, Luca begins trying to persuade Giulia to race without Alberto, proposing that Giulia can swim and he’ll take over both the eating and biking. Luca begins talking so fast. To get him to stop and calm down, Giulia throws a glass of water at Luca but it only manages to splash his hands. Luca and Giulia look at Luca’s scaled and webbed hands. It was at that point that Giulia found out that, like Alberto, Luca was also a sea monster, this time unafraid as she knows the two mean no harm towards anyone. Luca tells Giulia that he can explain while drying his hands. Giulia is furious with the fact that out of anywhere they could’ve visited, they visited Portorosso, where everyone hunts and, should the need arise, kills sea monsters. With no choice, Giulia sends Luca away for his own good and safety. Luca tells Giulia that she doesn’t understand. Giulia agrees saying she doesn’t understand why he and Alberto are risking their lives for a Vespa. Luca explains that his parents were going to send him away. Luca then states that it didn’t matter anymore. Luca finally agrees and leaves sadly, telling Giulia goodbye and that he is sorry.
Later on, Luca sits on the shoreline where Alberto revealed himself alone, ashamed of what he had done. Luca looks off at the Isola del Mare. He decides to go look for Alberto. Jumping into the water, Luca sets out to find Alberto. He swims to the island and dries off. Luca then walks over to Alberto's hideout. The ladder to the hideout had been tipped over and broken. Luca, instead, scales the wall using the protruding bricks. When Luca makes it to the top, he calls for Alberto, as he sees that the place has been trashed, almost every item is destroyed. It looked as if Alberto was in a rage. The Vespa drawing Alberto drew was found on the floor, ripped in two. Alberto, back in his human form, calls from the top of the tower, asking Luca what he's doing there. Luca looks up. Luca then apologizes to Alberto, saying he wished he could take it back. Alberto, still angry at Luca's betrayal, tells Luca coldly that he got the message and to get out and leave him alone. As Alberto walks out of view, Luca notices the Vespa poster is on the ground, and in its place, there are tally marks on the wall, 383 of them. Luca wonders what the marks mean and goes up to question his friend about the marks. Alberto is reluctant, curling himself up. After Luca asks again, Alberto explains that he started counting when his dad left, but he never seemed to come back. Luca asks Alberto if he had been alone for that long. Alberto, beginning to tear up, said that his dad stopped coming. He hoped that his dad would come back but he left it, saying that his dad was better off without him, including Luca. Luca tells Alberto that it isn’t true. Alberto disagrees. With tears in his eyes, Alberto states that Luca is always the good kid everyone loves and he’s the kid that ruins everything. Luca comforts Alberto, telling him to remember the "Silenzio, Bruno!" thing he taught him. Luca tries to lift Alberto’s spirits by reminding Alberto about their dream of having a Vespa. Alberto. However, angrily tells Luca to drop it, adding in that they should've never become friends in the first place. Luca tries to comfort Alberto, by touching his shoulder, but Alberto slaps his hand away, telling him once again to get out and not make him say it again. Luca then agrees and says he’ll enter the race and win the money for the Vespa. Alberto tells Luca that the idea is crazy. Luca says that he might be crazy and re-enacts when Alberto showed him gravity, by jumping off into the tree. Luca lands face first on the ground. Alberto asks what he's doing, with Luca responding that he fine and that he was going to fix everything.
It is now the day of the race. Luca is at the sign up booth, trying to reconsider with Signora Marsegleisse, determined to make it up to Alberto. Giulia finds Luca and asks him what he’s doing there. Luca tells Giulia not to worry. Giulia finds out that Luca has decided to be a part of the race, this time splitting up the team to go alone, as it was too risky to keep his sea monster identity a secret and getting Giulia involved into the problem. Giulia panics and tells Luca that he can’t swim. As everyone warms up, Luca shows up in Alberto’s diving suit, to avoid transforming into a sea monster in the water. Everyone stares at Luca and his bizarre swimming attire. Ercole laughs at Luca, as Giulia tells him it’s not a good idea. Ercole further pesters Luca, asking him if he can’t afford a proper swimsuit. Luca looks a bit scared at Ercole but his face quickly changes as he is determined to win the race for Alberto. Signora Marssegliese then announces that the race is about to begin. She adds in that since there have been sightings of sea monsters lately, they have hired fishermen to keep guard, harpoons in hand. Luca gets scared. He lowers his head in fear. Luca shoots a look at Giulia who shakes her head afraid for Luca’s life. When Signora Marssegliese gives the ring to go, all the swimmers run into the water, Giulia as well. With a deep breath, Luca secures the helmet of the suit and goes in. Luca doesn’t swim, however. Instead, he walks at the bottom of the ocean. A sudden leak causes water to begin flooding the suit, transforming him. When Luca comes out, he gets tripped by Ercole. When he realizes that the helmet had been knocked off in the fall, he retreats his head into the suit. Luca climbs under the table.
Once dry, Luca begins the pasta eating segment of the race, the segment Alberto was supposed to do. Luca struggles a bit with the pasta eating, but after Giulia shows him how to eat pasta the right way, he manages to finish and eats his pasta. Luca then begins the bike riding segment as he hops on his bike. After a loud burp, Luca begins pedaling with all of his might. Thunder is heard as clouds begin to cover the sky. Luca runs into his parents, but manages to get away, apologizing and saying he had to do this. Luca manages to surpass Ercole but just as he gets in the lead, it begins to rain. Droplets fall on Luca and he begins to transform. Luca then seeks refuge under an awning in the rain. Luca is disheartened, realizing how close he was. As he looks on, he hears his name called in the distance and notices a blue umbrella in the rain. Luca squints his eyes as the person lifts the umbrella, revealing it to be Alberto, running back for Luca who becomes happy to see his friend again.
Ercole comes up and pesters Luca, asking him if he was afraid of the rain. Alberto catches his attention, yelling “hey!” Ercole, fed up with the two, tells them that they down belong and to get out of his town. With a swift moves, he kicks Alberto in the cheek, causing him to drop his umbrella. Alberto falls on the street and soaked in the rain, he transforms back into a sea monster. Luca’s eyes widen in horror, as Ercole immediately stops, screaming "sea monster." Alberto looks up as people scream in fear and a mother picks up her child. Luca wants to ride over to help but not willing to let Luca come and risk himself getting caught too, Alberto tells Luca to stay put, and that he's still okay. Alberto then starts screaming happily while flailing his arms around, running towards Ercole. Luca calls Alberto’s name. Ercole then throws a net over Alberto and he falls hard on the ground with a grunt. Luca narrows his eyes, angered by what they did to Alberto. Seeing his friend trapped and helpless, Luca puts his feet on the pedals of his bike and races towards Alberto in the rain. As he does, the rain gets Luca wet, transforming him in front of everyone into a sea monster. Everyone turns and Alberto lifts the net up his face as Luca gut wrenchingly reaches for Alberto's hand. Alberto reaches for Luca and the two manage to hold each other. Luca manages to land Alberto on his bike. The two ride through town. Ercole catches up to them, harpoon in hand, screaming that he was going to kill him self some sea monsters, while laughing evilly. Giulia, who is right behind Ercole rams her bike into Ercole's, knocking him and her off their bikes which Luca and Alberto notice. Alberto yells Giulia's name as Luca halts the bike. They both run to her, with Giulia's dad getting a harpoon to kill the sea monsters.
However, as he gets nearer to them, he notices that their faces aren't unfamiliar to him. Massimo notices that the sea monsters he was readying to kill were actually Luca and Alberto. Everyone surrounds them with harpoons. Ercole comes out of nowhere saying he saw them first so he gets to kill them. Luca firmly states that they’re not afraid of them, with Alberto stiffening up in response. Ercole says that they might not be afraid, but that the people are afraid, horrified and disgusted by Luca and Alberto because they are "monsters." Luca looks sadly at everyone with the harpoons, realizing that Ercole is right. Giulia screams to stop and that they are not monsters, with Ercole asking who they are then. Massimo comes out, claiming he knows. He looks at the kids, first at Luca, then at his daughter, and then Alberto, before proclaiming them as Luca and Alberto and the winners of the race. Ercole says that they can't have won, saying that they aren't people. Massimo has Signora Marssegliese determine if so or not. The bike that Luca and Alberto abandoned is across the finish line. She proclaims that technically and legally, they won. The trio look at each other, happy, as Ercole says that it doesn't matter and they're sea monsters. Fisherman get close with harpoons. However, Massimo comes behind the trio, causing everyone to drop their harpoons.
As Ercole stares in disbelief, Luca, Alberto and Giulia grab and destroy his harpoon. Ercole orders for Ciccio and Guido to grab him another and insults them by calling them idiots and tells them to "be useful for once in their pathetic lives". Fed up with Ercole's abuse, Ciccio and Guido throw him and his wool sweater into the fountain. Giulia declares the reign of terror over. Luca's parents come out and transform in front of the crowd. Daniela loads on Luca saying that he had them scared. Luca apologizes but Daniela goes on to tell him that he did so well in the race, raising his tail up and “kicking so much human butt.” She hugs Luca saying that she's so happy but still mad at him for sneaking off. In the end, Daniela cries, relieved that her son is okay. Luca puts his hand over her back proclaims he loves her and embraces his mother, as his father hugs him. Daniela looks at Alberto and Giulia. Alberto just shrugs and doltishly smiles. Finally, the Underdogs are given their reward, a trophy as winners of the Portorosso Cup. The three begin rejoicing, happy to have won. Meanwhile, they receive applause from the crowd. Many kids begin running up to them, congratulating them. Luca looks on happy.
Later on, the three have fun on the Vespa, with Alberto messing around with the cat, Machiavelli, making it look like he's driving. Luca laughs so much that he falls to the floor. Giulia helps him up. Luca’s parents talk about how well he did but that he can’t stay in the surface. Luca’s grandma goes on to explain that many will never accept him, but some will and Luca seems to know who are the good ones. Giulia then asks Luca and Alberto where go first. Alberto explains that Luca and he will stay to repair it in order for it to take them around the whole earth. Giulia says to them to not forget to pack for it, but then remembers she forgot to pack to go to school. Luca sighs and sadly states that she'll learn so much. Alberto listens quietly. Giulia says that she'll lend Luca some books, Luca excited to hear so. Giulia leads and Luca tells Alberto to follow. As Luca and Giulia leave, Alberto looks down at the Vespa and smiles. He then follows Luca and Giulia.
It is now time for Giulia to leave. Giulia states how she’s amazed that they actually won the race. Alberto tells her that maybe they can race next summer. Giulia then says that maybe they can just have some fun. She hugs the boys. Luca and Alberto hug her goodbye. After a final goodbye, Giulia boards the train. Luca then asks Alberto if he's ready to fix the Vespa, but Alberto says that he has sold it while handing Luca a train ticket. Luca's family come and they tell Luca that if he writes to them every day and stays safer than safe, he can go to school. It was revealed that Alberto talked them into it, and according to Luca’s grandmother, it wasn’t easy to persuade them. Luca happily accepts. His mother reassures Luca, telling him that they’ll be there for him always. Luca reminds his mother that he loves her and wipes a tear from her eye. Luca is given his suitcase and happily heads to the train, telling Alberto to come, but Alberto isn't going. He tells Luca that it was the only ticket he could buy and that Massimo wants him to stay behind and help with fish, probably even move in. Luca is unsure, saying he can't do it without him. Alberto says that he already has been doing it and hands Luca the Vespa drawing they made, taped back together. Alberto tells Luca that whenever he jumps off a cliff or tells Bruno to stop bothering him, that will be him. Luca asks Alberto how he'll know he's okay. Alberto has no answer. Instead, he hugs Luca as tears stream down his face. Luca embraces Alberto tight, tears filling his eyes as well. Alberto comforts Luca, telling him that he got him off the island, and he'll be okay.
As Luca boards the train, Alberto then says the greeting he taught him one last time. Luca asks what it seriously means, and Alberto tells Luca he doesn't know and to find out for him. They both hold hands as the train departs. They eventually let go. Luca sadly watches as Alberto follows the train, with tears in his eyes, running. As he makes it into the rain, he transforms. Alberto begins screaming and cheering for Luca, waving goodbye with his hat to his best friend. Luca watches and listens to Alberto cheering him on down the tunnel. He gets one last look at Alberto. The train exits the tunnel and Luca makes it into the rain, where the rain transforms him. Luca cries, realizing how much he’ll miss Alberto. He wipes a tear from his eye. He then looks out into the ocean, to the Isola del Mare. The rain clouds don’t meet, causing a ray on sunlight to shine over the island, the same island where he and Alberto first met. Luca smiles, remembering Alberto and knowing their friendship and summer memories would live on forever. Luca then leans out of the train, feeling the rain with his arm as the train takes him to his next adventure.
- Luca is Pixar's fifth titular character, the others being Nemo, WALL-E, Dory, and Coco, as well as the third titular character to be a protagonist, the first two being WALL-E and Dory.
- The DisInsider initially reported that Portorosso was going to be Luca's surname, and possibly a reference to Porco Rosso.
- His actual surname, Paguro, is Italian for "hermit crab".
- Luca is based on Enrico Casarosa himself. He chose the name, Luca, over his own because he felt it would be easier for foreign countries to pronounce.
- Luca's design is loosely recycled from the character of Bambino from Casarosa's short film La Luna.
- Out of all the characters in the film, Luca has the largest eyes (proportional to his head) since he is so curious and eager to "take everything in."
- Luca has, in some ways, drawn comparisons to Ariel from The Little Mermaid. Both characters arguably suffer from boredom from living under the sea and find happiness when they come to the surface, where they have to hide their oceanic origin. The major difference is that Ariel is motivated by love, having fallen in love with Prince Eric, while Luca's motivation is adventure and discovery.
- Luca also shares some similarities to Pinocchio. Both characters arguably desire to be human, or at least be accepted as human. They are drawn into a rather intense life of debauchery and make mistakes before getting help from educated characters. However, Pinocchio ends up losing many people during his adventure while Luca is able to reform and help his. The Pinocchio comparison is somewhat hinted at in the movie.
- Early concept art seemed to imply that at one point, Luca lived on the island with only his mother, Daniela, who appeared younger and much more free spirited than in the final film. Additionally, Luca's dream was originally to work as a mechanic in a Vespa factory, instead of riding one around the world.
- Unlike Alberto’s fins, Luca’s caudal fins are rounded in shape. This a a physical reminder of Luca’s gentle and tender nature.
- This is also another hint that Luca is a bit more of a weaker swimmer than Alberto. Alberto’s fin design is more sharper (like the fins of a tuna) than Luca’s because Casarosa said that “[he] is a stronger swimmer.” Even still, Luca swims faster than the average human can.
- In the film, Luca has many imagination scenes. This was added by director Enrico Casarosa. He explained because of Luca’s meek and quiet personality, he thought the audience would have a hard time understanding him. Because of this, Casarosa concluded that the way for the audience to understand Luca was by taking them into his mind and to be able to physically see what he was feeling.
- Luca’s eyes obviously have two different forms, sea monster and human, but there is a detail. Luca’s irises are bigger when he is in his sea monster form. When he is in his human form, Luca’s irises shrink down a bit. Another noticeable detail is that Luca’s irises as a sea monster are a little more tinted maroon but in human form, they appear more lighter brown in color.