The Guardians of the Galaxy are a team of intergalactic super-heroes that exist in the Marvel Comics and Marvel Cinematic Universe. The team consists of Star-Lord, Rocket Raccoon, Groot, Drax the Destroyer, Mantis, Nebula and Thor Odinson.
Gamora, Groot, Rocket, and Star-Lord are taken to Kyln by the scandal they caused in Xandar. Arriving Peter is harassed by an inmate but thanks to the help of Rocket and Groot, the prisoner leave it alone. While all prisoners slept, Peter wakes up and sees that some prisoners attack Gamora, he sneaks and go to help Gamora.
Peter tries to convince Drax that no longer with Ronan, Drax believes him after the insistence of Star-Lord. The next day, the group plans the escape but the escape began much earlier by Groot, who took an artifact that was necessary for the end of the plan.
The group manages to escape after some complications and travel to Knowhere to sell the Orb. Before the meeting with the Collector, Drax and Rocket have a discussion that almost ends in tragedy, Star-Lord and the others will meet with the Collector but Drax turns away from them and call Ronan. Having lost the Orb, the Guardians and the Ravagers join to recover the gem and save Xandar.
During the battle of Xandar, Groot give his life to save his new friends from a certain death, when it seemed that Ronan had been defeated, the Kree appears in the rubble. Peter distracts Ronan allowing Rocket and Drax destroy the Universal Weapon.
Quill immediately grabs the Orb that almost killed him for his power, but his teammates hold his hands to help to defeat Ronan, The Accuser didn't understand how simple mortals could withstand the power of an Infinity Stone, then using the power of the Orb to disintegrate and defeat Ronan finally.
Two months after the battle on Xanthar, the Highest Priestress of Sovereign, Ayesha, hires the Guardians of the Galaxy to fight with the Abilisk, a dimensional creature on the Sovereign planet. During the battle, Quill, Gamora, Drax, and Rocket fight the Abilisk while Groot in his baby form dances to "Mr. Blue Sky". Later, Drax is punched by the Abilisk and accidentally bumps himself on the speaker Groot was listening to. Drax lets himself get swallowed by the Abilisk and cut the inside, which proves to be a fruitless attempt as the Abilisk's inside was as impenetrable as its external skin. They later lose the energy of their weapons but Gamora cuts into a ound the Abilisk sustained, killing it and freeing Drax. Ayesha gives thanks to the Guardians and trades Nebula as their reward. However, Rocket steals the Sovereign's Anulax batteries for himself, prompting the Sovereign to send a fleet of Sovereign Drones to attack the Milano to procure their stolen items. During the dogfight, the Milano escapes from the drones but crashes on Berhert.
On the planet, the Guardians were greeted by a being named Ego who helped the Guardians escape the Sovereigns to meet his son, Quill. Quill, Gamora, and Drax later join with Ego and Mantis on their destination to Ego's Planet. Back on Berhert, a clan of Ravagers led by Yondu Udonta were on the way to capture the Guardians for stealing the batteries under the command of Ayesha. While fighting Rocket, Yondu's leadership is seized by Taserface when Nebula shoots shot Yondu's fin, and joins the Ravagers with Rocket and Groot as prisoners.
On Ego's Planet, Ego welcomes the team and begins bonding with Quill to teach him about the Celestial's ability and powers. Drax finds himself bonding with Mantis, while Gamora is still doubtful about Ego's intentions. When communication with the other Guardians fails, Gamora tries to find out more about the planet. Unfortunately, she sees Nebula approaching the plant as the latter proceeds to kill Gamora at last. Gamora evades and shoots down Nebula's ship, but Nebula is not as lucky; her ship breaks down in the cavern she cornered Gamora in. Despite her hostile feelings, Gamora ultimately rescues her sister from the ship before it explodes, causing Nebula to finally give up her grudge against Gamora and the two make up.
On the Eclector, Rocet, Groot, and Yondu were kept for interrogation and entertainment by the Ravagers as they would get delivered to Ayesha. However, while the crew is asleep, Rocket and Yondu try to get Groot to retrieve Yondu's prototype fin. But instead of Groot, Kraglin gets the fin and helps them escape by using the Quadrant.
Back on Ego's planet, Mantis decides to confess the dark secret Ego has been hiding due to her trust in Drax. Meanwhile, Gamora and Nebula discover thousands of skeletons in the cavern, belonging to the children of Ego who had failed to inherit his Celestial genes. It is then revealed that Ego's true plan was to get Quill to unlock his Celestial powers so that Ego's influence could spread across the universe through the seedlings Ego planted, uniting the planets into Ego's form. Quill refuses to help carry out his father's plan, so Ego resorts to forcefully draining the energy from Quill and begin his planetary assimilation.
Luckily, Mantis, Drax, Gamora, and Nebula arrive at the scene to try and save Quill, with Yondu, Groot, Kraglin, and Rocket arriving afterwards with their ship. Though the team destroys Ego's avatar, they realize they must destroy the planet's core as it was the source of Ego's power. While they were on the way to the core, a fleet of Sovereign Drones attack the ship that they were riding. During the battle, Quill fights with Ego using his Celestial powers while Gamora, Yondu, Drax, Mantis, Rocket, and Kraglin hold off the Sovereign. Due to his size, Groot delivers an atomic bomb on the core and sets it to detonate in five minutes. While the other Guardians sans Yondu manage to board the ship in time, Gamora tries to go back to save Quill but is stopped by Rocket, unwilling to lose any more allies that day. Quill finally manages to defeat Ego as the bomb sets off and destroys Ego's conscious with the rest of the planet. Before Quill is caught in the explosion, he is unexpectedly rescued by Yondu, who gives up his remaining space suit to let Quill survive in space, sacrificing himself.
A funeral is held for Yondu, where he is honored as a fellow Guardian by the team while the rest of the Ravagers pay their respects. Nebula decides to leave the team following Yondu's ceremony, although she leaves on good terms with Gamora and vows to stop Thanos herself. Mantis and Kraglin decide to join the team, where Kraglin inherits Yondu's fin and arrow as his own.
While responding to a distress call, the Guardians discovered the remains of an Asgardian refugee ship, where they retrieved the seemingly-dead body of Thor, who was awoken by Mantis. When Thor explained that Thanos had been responsible for the attack, claiming the Space Stone from Loki after previously acquiring the Power Stone, the Guardians decided to return to Knowhere to ensure the security of the Reality Stone. Rocket and Groot departed in a pod to take Thor to a legendary forge where he could acquire a new hammer to kill Thanos, while the other four travelled to Knowhere, Gamora asking Quill to kill her if it looked like Thanos was going to take her prisoner. Unfortunately, they arrived too late to stop Thanos taking the Reality Stone, the Mad Titan using his new power to effortlessly thwart Quill's attempt to kill Gamora before he left.
With Gamora forced to take Thanos to the location of the Soul Stone- which she had discovered a map to long ago- Quill, Drax and Mantis travelled to Titan to try and corner Thanos, guessing that the planet was his base. Upon arriving, they discovered a ship belonging to the Black Order, but a brief fight with the ship's inhabitants revealed that they were Thor's teammates on the Avengers; Iron Man, Spider-Man and Doctor Strange. Confirming that they were each enemies of Thanos, the six made plans to take the Gauntlet from Thanos when he came to Titan, based on Strange's analysis of the future through his own control of the Time Stone.
While Rocket and Groot helped Thor and Eitri restart the forge to create his new hammer, Stormbreaker- Groot 'donating' an arm to complete the hammer's handle- Gamora was forced to take Thanos to the world where the Soul Stone was hidden when he threatened Nebula. They found that the Stone was guarded by the Red Skull, who warned that the Stone could only be claimed if the seeker sacrificed something he truly loved for it. Gamora believed that the need for such a sacrifice ensured that Thanos would never be able to take the Stone, but Thanos proved Gamora wrong when he sacrificed her for the Stone. When Thanos returned to Titan, he was confronted by the assembled Avengers and Guardians, but although Iron Man and Spider-Man almost got the gauntlet off while Mantis used her powers to keep Thanos unfocused, when Nebula appeared and revealed that Gamora was dead, Quill attacked Thanos in a rage, allowing him to gain the advantage in the fight, forcing Strange to surrender the Time Stone to save Stark's life.
When Thanos's forces on Earth attacked Wakanda to claim the final Stone from the Vision- who was currently undergoing 'surgery' to remove the Stone so that it could be destroyed by Scarlet Witch- they were opposed by the Avengers and the Wakandan army, who were able to defeat the remaining members of the Black Order. Thor was able to travel to Earth with Groot and Rocket, with his new weapon almost helping him to gain the upper hand on Thanos, but despite the best efforts of the various heroes, Thanos was able to claim the Mind Stone from the Vision. With the Gauntlet complete, Thanos triggered the deaths of half the living population of the universe, the process killing all of the Guardians of the Galaxy apart from Rocket.
After the heroes learn that they cannot undo Thanos's actions, Rocket and Nebula essentially 're-form' the Guardians of the Galaxy under the Avengers' banner, coordinating their efforts to stabilize what remains of the universe with the heroes on Earth. However, after the return of Scott Lang provides the heroes with the possibility of going back to retrieve past versions of the Stones to reassemble the Gauntlet, Rocket and Nebula return to Earth to contribute their knowledge of the Stones' history. Rocket accompanies Thor to Asgard prior to Malekith's attack to extract the Reality Stone from Jane Foster while Nebula joins James Rhodes in retrieving the Power Stone, but Nebula unwittingly jeopardizes the plan when her cybernetic components wirelessly link up with those of her past self, which alerts Thanos to his future victory and their current efforts. Although the Avengers are able to reassemble the Gauntlet and the Hulk undoes Thanos's efforts, Nebula was able to switch places with her future self and help Thanos travel to the future so that he can use the Gauntlet to remake the universe himself. Fortunately, Doctor Strange was able to teleport the resurrected Guardians to the Avengers Facility to help oppose Thanos's forces, which include the alternate version of Gamora that came to the present with Thanos.
After Iron Man sacrificed himself to use the Infinity Stones and eliminate Thanos and his army, the Guardians of the Galaxy attend Stark's funeral before they depart Earth, with Nebula and Thor now official members of the team as Quill begins his search for Gamora.
The Guardians of the Galaxy were sent to the Earth to hunt Korvac, a human who gained cosmics powers behind Kree experiments. The Guardians located Korvac in the Avengers Mansion. The Avengers and The Guardians held a battle between them, a battle was stopped by Hawkeye, after learning the truth about Korvac.
The heroes joined forces but Korvac was very powerful and easily defeats them, after that Korvac goes to another dimension, the Guardians left the Earth.
Rocket goes to Earth to recruit Nova to help them to confront Korvac and his Chitauri's army, Rocket and Nova leaves but Spider-Man joins them. The Guardians battle the Chitauri an alien race led by Korvac. When Rocket Raccoon's ship is pulled into the Chitauri ship, Rocket fakes surrender so that they can free the captive Guardians of the Galaxy members.
Afterwards, Spider-Man discovers that the Chitauri are planning to destroy the Earth. The Guardians plan to run the Chitauri ship into the sun while fighting the Chitauri forces. When their tactic does not work, the Guardians end up making their way towards the Dark Matter Cannon. While Nova and Spider-Man head to the Dark Matter Cannon, the Guardians fight the Chitauri and Korvac.
After the battle, the Guardians ask Nova to join them, Nova seem to accept the offer to be a Guardian, but eventually Nova decides to estay on Earth with his friends.