As Della rebuilds her ship, Penumbra becomes convinced Della’s planning an attack. Meanwhile, Donald's nap keeps getting interrupted by adventure.
On the moon, Della skips across the craters carrying a bag of gold. Penumbra is watching via binoculars as Della is continuing work on her rocket and almost stops to rest but fights the urge, while Penumbra suspects something is amiss.
Meanwhile on Earth, Donald is setting up a hammock and rests while listening to Hawaiian music and reading his book. Suddenly, Webby and Huey surprise him, but the duck reminds them his hammock is a prescription for his molting condition. Because Donald needs to rest, Webby requests they watch his old VHS tape of The Necronomica Set. Donald decides to let the kids watch his horror tape, when the grounds shudders violently and hands reach out to Donald, scaring him away.
Back on the Moon, Lunaris continues to offer Della a home within his society, but Della reminds him of the times she bunked with Donald back home on Earth. Determined to collect more gold to fix her ship, she spots a statue of Lunaris and Penumbra. Lunaris explains how Penumbra is a hero on the Moon, but then Penumbra nearly gets into fisticuffs with Della as the Moon Mites have stopped their raids on Tranquility.
Della then goes back to work leaving Penumbra to seethe. Penumbra then attempts to warn Lunaris that Della is a spy planning a devious attack on the Moon. Lunaris explains that years back, his father was afraid of objects flying off the Earth and wanted to hide underground. As Penumbra continues her suspicions, the Moonlander General hopes his people will rise again from fearing Earth. As Della is resting, Lunaris orders his lieutenant to take her under her care.
On Earth, Huey and Webby are being chased by zombies when Donald comes to their aid with a hand-mounted chainsaw. However, the zombie's torso still alive attacks Donald. Desperate, Huey reads a mystical incantation and banishes the zombies back to the ground, nearly taking Donald with them. Huey assures his uncle that everything is fine, and Donald accepts it tearing the zombie's attached hand off. As Donald goes back to his resting, the kids learn his molting condition is worsening by the minute.
Donald attempts to hide his baldness on his houseboat and rests on his hammock once again. Just then, Dewey startles Donald awake wearing the flying Sandals of Hermes. Storkules informs Donald of Dewey's latest achievement, but then Zeus's lightning strikes having declared war on Dewey. The blue shirted duck and Storkules set out to resolve the issue when a bolt hits Donald forcing him to jump into the swimming pool.
Back on the Moon, Penumbra observes the statue of her and Lunaris when Della calls out to her. After nearly getting shot, Della is delighted how Lunaris gave her a place to stay. In Penumbra's home, Della fiddles with the lieutenant's weapons and examines her golden spear. Taking some gold for more work, Della believes she and Penumbra have spears causing the Moonlander lieutenant to chuck her spear.
While working, another Moonlander named Gibbous meets with Della recognizing her as the one who saved the city with her "Earth ways". He and his wife Zenith are curious as to how compassion could be a fighting technique. When Della says she is trying to get back to Duckburg to meet her kids, the Moonlanders offer assistance. This begins to anger Penumbra. As Della continues working, she tells of how she fought Beagle Boys in the past and strung them up from a bank before. Gibbous is also curious when Della mentions "yo-yo" and "dog". Penumbra feigns friendship as the mother duck sees shenanigans in their future.
As Della says the Moon and the Earth can both be great, Penumbra nearly shoots her but starts a fire instead. Zenith is then eager to learn more about Earth. Della explains that her family is back home, and there are wonders such as the pyramids, humpback whales and slap bracelets; Della applies one of such bracelets to a dark purple Moonlander named Palus. As Penumbra tries to restore order, the mother duck hopes to explore places such as Mt. Neverrest and Toth-Ra's tomb and says her family is fearless.
Back on Earth however, Donald's party is in trouble with Zeus and the worrysome duck wants to ditch the fight. Dewey then begins to insult Zeus and Donald insists on being used as a projectile against the god anyway.
On the Moon surface, Penumbra practices throwing her spear at an effigy of Della in a fury. More Moonlanders gather, causing Penumbra to suspect a trap. Della tells of how she fought and defeated a giant Gilded Man robot that was terrorizing El Dorado. Some of the Moonlanders are happy that none of the adventures Della had in the past had happened before in tranquility, when Penumbra corrects them as the city is not "Robot Monster Town". As the purple Moonlander wonders about what Della says is true, the duck says she took care of the robot before.
Before Penumbra can run Della through though, Lunaris advises that Della is to have an adequate stay on the Moon. As the lieutenant grows more perplexed that the population is accepting Della's stories as the Earth is better than the Moon, Lunaris assures she can share the cultures of Earth. The general also points out the emergency launch button which if activated, will send the Spear of Selene flying off the Moon.
Back at McDuck Manor, Zeus concedes and Storkules embraces Donald for another accomplishment. The sailor uniformed duck then walks away to try and get rest. He next attempts to sleep in Scrooge's closet with the hammock when Scrooge spots a suspicious goat in between Donald and Louie. The "goat" is actually a being from Goat'hool, a realm of never before seen treasures and dangers like orcs. The being also offers the chances for the ducks to be kings; Louie accepts, with Scrooge looking to find some treasure, and Donald tries to reject before he is swept into the Goat'hool gateway.
Still on the Moon, Della tests her rocket before the Moonlander crowd to make sure it works, and indeed it functions. To her delight, Della thanks the aliens for their help as she can finally make it home to her family. Penumbra then says that if Earth is a great place, she insists they go. Gibbous is then eager to get a dog which Zenith could dress in slap bracelets. But Della informs the crowd that the rocket cannot take that much people. The Moonlander lieutenant then says Della could do it if she wished to do so. While Della is not embarassed by the Moon cultures, she knows bringing a crowd is impossible. As the Moonlanders are about to depart, Della believes it may be possible to try and see if she can fit an entire crowd. Penumbra then furiously snaps her spear in two.
On Earth, Scrooge's party returns from Goat'hool and the elder duck says true royalty is found within. Louie believes the real king would not need his crown, but the Goat'hool being from earlier confiscates it. With Donald now more panicked than ever and his head feathers molted off, he tries again to assure everything is fine. However, the kids burst in with the possibilies of more adventures but Donald storms out of the room with his hammock and some of his feathers flying off him. The kids and Scrooge begin to feel concern for the uncle duck.
In Tranquility, Lunaris is about to try on his slap bracelet when Penumbra barges in concerned for the safety of the people and how much hard work they have put into the city. Lunaris says that his people are free to make their decisions. As Penumbra continues to denounce Della, the mother duck appears and shows she repaired Penumbra's training spear, as a way of repayment. She next shows her attempt at drawing what her kids look like even though she is not a good artist. Della also tells Penumbra that she herself could protect her people better, and the former says she would do whatever she could to keep the Moonlanders safe.
On his houseboat, Donald realizes sleeping on his prescription hammock has had anemic and ineffectual results and dumps it into the garbage. When his door is knocked on, Donald shrieks fearing how his other family members will react to his baldness. Just then, the kids, Scrooge and Storkules are throwing a going-away celebration as thanks to Donald for taking care of them for so long. Therefore, Scrooge has scheduled Donald to be on a month-long Caribbean cruise on the S.S. 40-Winks, which promises neither phones or adventure but lots of hammocks. Donald is concerned that the kids will get into trouble while he is away, Huey assures the family can keep the triplets out of trouble in his absence. The uncle then has time for a goodbye group hug to the kids.
Back on the Moon, Penumbra mumbles to herself that Della may not be entirely evil yet it still worried for her people and throws her spear in frustration. Seeing her spear fly off in the distance, Penumbra decides to bring Della back to her rocket while she is sleeping. After a moment of pondering, Penumbra activates the emergency launch. Della wakes and says she would clean dishes, but then sees her rocket about to take off. As the emergency launch can not be aborted, Penumbra solemnly tells her roommate to return home to her own family back in Duckburg. Lunaris sincerely wishes to build more Spear of Selene replicas provided Della hand him the owner's manual. Having inspired the Moonlanders, Della hands Lunaris the manual, hugs Penumbra and gets back into the rocket, just as the hatch closes then launches the Spear of Selene and Della off the Moon. With a look a determination and tears streaming from her eyes, Della announces she will finally make it home to her boys and races back to Duckburg at top speed.
Moments after the rocket has left, laser fire rings out as Lunaris had shot himself in the left arm. The Moonlanders who had packed their belongings are saddened that the rocket is gone. Lunaris then informs the crowd that Della has deceived them with wondrous stories of her so they would aid her in rebuilding the Spear of Selene. He then says that Della attacked him. Lunaris then says all of her stories were an act of deception, calling Della the "first wave" of invasion from Earth and would scurry home to tell Earth they are weak. Lunaris then says he and his people would not wait for attack, so with the Spear of Selene's manual he will prepare a fleet of rockets and declare all-out war on Earth. With the war underway, Lunaris vows to prove the Moon is the "Greatest Planet in the Universe". Penumbra is now concerned that war will soon break out.
Confronting Lunaris in his chambers, Penumbra suspects a setup as Lunaris brought Della and her ship to their city and she gained their trust. Lunaris then says that with the other Moonlanders not being warriors like they are, he needed to give them mutiny as a reason to fight; He also has the Spear of Selene's manual. When Penumbra tries to protest, Lunaris reminds her he would not stand idly by and fear Earth as his father did and make the planet fear him instead. Lunaris paired Della with his lieutenant to attempt to persuade her to live in Tranquility forever as Penumbra reminded Della of her brother, Donald. Lunaris then leaves to begin invasion preparations while Penumbra stares at the Earth with worry.
At the bus stop outside McDuck Manor, Donald fiddles with his Caribbean brochure when he spots the Spear of Selene falling to Earth for the first time in a decade. Racing to the crash site, Donald calls out to Della excitedly only to find her absent from the rocket. His bad luck gets the best of him when he unexpectedly activates the launch sequence (deja vu). Donald's attempts to abort the launch are in vain and for the second time in its condition, the Spear of Selene flies away but with Donald in the cockpit. After what seemed like an eternity, Della finally reaches the outer grounds of McDuck Manor and announces she is home for the first time in years.
- David Tennant as Scrooge McDuck
- Danny Pudi as Huey Duck
- Ben Schwartz as Dewey Duck
- Bobby Moynihan as Louie Duck
- Kate Micucci as Webby Vanderquack
- Paget Brewster as Della Duck
- Julie Bowen as Lieutenant Penumbra
- Lance Reddick as General Lunaris
- Tony Anselmo as Donald Duck
- Chris Diamantopoulos as Storkules, Mythical Goat
- Michael Chiklis as Zeus
- Rob Paulsen as Gibbous
- April Winchell as Zenith, Spear Computer
- Laura Bailey as Palus
- Kari Wahlgren as Roxanne Featherly
- Sam Riegel as Moonlanders
- The events of The Impossible Summit of Mt. Neverrest! and The Living Mummies of Toth-Ra! are mentioned by Della, talking of all of the adventures she would love to do with her boys when she gets back to Earth, even though they already had them in Season 1.