We open on Knowhere, a giant skull-asteroid that has become the base of operations for the Guardians of the Galaxy. Rocket Raccoon (voice of Bradley Cooper), singing along to Radiohead's "Creep" on Peter's Zune, is clearly at a low point; so is Peter "Star-Lord" Quill (Chris Pratt), who has grown increasingly drunk due to the loss of his beloved Gamora. Groot (voice of Vin Diesel) has grown to a human-sized, broad-chested adult, and Drax the Destroyer (Dave Bautista) and Mantis (Pom Klementieff) are continuing their friendship, with Kraglin (Sean Gunn) struggling to control the yaka arrow he got from his mentor and arguing with Cosmo the Spacedog (voice of Maria Bakalova); and Nebula (Karen Gillan) has taken over Gamora's spot on the roster and become the Team Mom. The Guardians of the Galaxy still exist... but they aren't doing much. And, as though to hammer home the tonal change from the first two movies, no one dances during this opening.
The High Priestess of the Sovereign, apparently still salty that the Guardians stole her harbulary batteries (see Guardians of the Galaxy Vol. 2), activates her culture's greatest creation: Adam Warlock (Will Poulter), an artifically-created Flying Brick with Hand Blasts. Adam attacks Knowhere, showing not only his power as an opponent but his mentality as someone who Really Was Born Yesterday; the Guardians succeed in driving him off, but Rocket is grievously wounded. Even worse, they cannot use a standard medpack on him as his creators, "Orgocorp," embedded a kill-switch in his physiology. The remaining Guardians resolve to raid Orgocorp HQ and figure out how to save him.
While in his artificially-induced coma, Rocket has flashbacks to his own youth. He was plucked out of obscurity by the High Evolutionary (Chukwudi Iwuji), a scientist who wants to create a perfect society and is using Evolutionary Levels to do it. Rocket gained the High Evolutionary's attention by showing much more insight and creativity than any of the other animals who were experimented on, most of which are now cyborgs: a rabbit with metal spider legs who calls herself Floor (voice of Mikaela Hoover); a wheelchair-mounted walrus named Teefs (voice of Asim Chaudry); and an otter with replacement metal arms, Lylla (voice of Linda Cardellini), who becomes Rocket's best friend.
The High Evolutionary, who also created the Sovereign, intimidates the High Priestess into helping him apprehend Rocket. Meanwhile, the Guardians break into Orgocorp HQ with the help of some Ravagers: their leader, Stakar Ogord (The Cameo of Sylvester Stallone), loans them his latest lieutenant, none other than Gamora (Zoe Saldaña). She doesn't give a damn about the Guardians, and especially not Peter, but she and Nebula are still close; The Glorious War of Sisterly Rivalry between them is over now. Peter is still pining after his Lost Lenore, but Gamora points out that, due to the time-travel shenanigans of Avengers: Endgame during which she (Gamora) was brought forward from 2014 to 2023, she simply isn't the same person as the Prime Timeline Gamora, who died in 2018 and has stayed that way. After a quick altercation with head of security Master Karja (Nathan Fillion, in the opening credits despite being a One-Scene Wonder), they determine that the info they need has been deleted from Orgocorp's files. They identify one of the High Evolutionary's aides, Theel (Nico Santos), as having the information. (They also have to fight their way out, because it's a superhero movie.)
Rocket's flashbacks continue. The High Evolutionary wants to populate his perfect society with evolved versions of animals, but all of them get possessed with Unstoppable Rage. Rocket's intelligence allows him to pinpoint a solution... but the High Evolutionary, rather than being impressed with his creation, instead gets jealous. He sends Rocket back to the holding pens pending dissection, and orders Lylla, Teefs and Floor incinerated. Rocket, with an improvised keycard, breaks the pens open, and prepares to lead his friends to the shuttlebay to commandeer an escape craft... but the High Evolutionary arrives and shoots Lylla dead. And then mocks Rocket as he sobs over his closest friend. Rocket goes on the offensive, attacking the High Evolutionary's face and killing the mooks... but the damage is done, and both Teefs and Floor have been slain in the crossfire. Rocket makes his escape, alone. The Cynicism Catalyst has produced the Rocket Raccoon we've seen from the beginning — sarcastic, closed off, self-loathing.
The High Evolutionary has gone to "Counter-Earth," an artificial planet he's created to house his "perfect" society, and the Guardians decide to go there. Not Gamora, though; she's not interested in this whole "helping Rocket just because we're his friends" thing, and she radios her contact within the Ravagers for extraction. This only works out so well for the contact: he's been captured by the High Priestess and Adam Warlock. The High Priestess asks Adam to "show him we mean business"; she presumably meant Torture Always Works, but Adam, who Really Was Born Yesterday, assumes this means to Leave No Survivors — to the panic of the High Evolutionary and the Puppy-Dog Eyes sadness of the Ravager's pet, the cute and fuzzy Blurp. ("I really don't enjoy how that's making me feel, actually.") But his radio still works... And the High Priestess, pretending to be a Ravager, agrees to pick Gamora up at Counter-Earth. Adam, meanwhile, adopts Blurp, despite his mother's protests.
Quill and Groot surrender to the High Evolutionary in order to get their hands on Theel and his cybernetic implant; the plan is a success. However, everything else goes wrong: the High Evolutionary, displeased with the imperfect iteration of his society, has it purged, and Rocks Fall Everybody Dies. Adam Warlock tries to steal Rocket's comatose form from the Bowie, and Gamora fights him off, but she is forced to fly the ship as the ground starts to explode; meanwhile, Adam, realizing what's going to happen, races off to try to save the High Priestess before her ship gets wiped out. He is unsuccessful. Meanwhile, Nebula, Drax and Mantis, who were outside the Orgocorp HQ, jump onto it when it reveals itself to be a ship, the Arête, escaping certain death but leaving them stranded in the enemy's stronghold.
Gamora picks up Peter and Groot, and Peter tries to use the code to disconnect the killswitch. Rocket flatlines, as Quill bellows out the Big "NO!", he goes to a White Void Room afterlife where Lylla, Teefs and Floor have been enjoying their freedom. Rocket asks if he can join them. Lylla says he can... Eventually.
- Lylla: You still have a purpose here. ... This story has been yours all along. You just didn't know it.
Peter and Groot gather the revived Rocket into a hug. Nebula, overhearing the events on the comm, suppresses Tears of Joy. Even Gamora smiles. The Guardians of the Galaxy are finally back in action.
In the belly of the Arête, Nebula, Drax and Mantis begin to squabble. Nebula is tired that, in her opinion, Drax doesn't carry his own weight, but Mantis points out that he's the only member of the Guardians who doesn't hate himself. Drax further shows his Hidden Depths when they encounter a bunch of alien kids: besides being a Friend to All Children, he's the only one who can speak their language, and he helps them spread the word that rescue is coming.
And rescue is coming: Quill brings the Bowie in (with Adam hanging out onboard) for a frontal assault while Kraglin warps in Knowhere — like, the whole planetoid — to flank, even the odds, and blow open a hole through which the Guardians can board. The High Evolutionary deploys "hellspawn" mooks to defend his ship, and they almost overwhelm the defenses on Knowhere before Kraglin, inspired by the memory of Yondu (Michael Rooker), masters the yaka arrow and takes them apart almost instantly. Meanwhile, Nebula's team are menaced by Abilisks — the giant tentacly things from the intro to the second movie? — but Mantis manages to bond with them. Quill's rescue mission to save the three therefore ends in about 15 seconds when they ride in on their new mounts. Quill therefore changes the orders to immediate withdrawal, but Rocket protests: "I'm done running." He charges his weapons and leads the Team Power Walk, with the other Guardians — even Gamora, after an eyeroll — falling in behind him. What follows is an Epic Tracking Shot as each member of the team — Multi-Armed and Dangerous Groot, All Asians Know Martial Arts and Mind Controller Mantis, Guns Akimbo Fragile Speedster Rocket, Genius Bruiser Quill, Cyborg Nebula, Stone Wall Drax and sword-wielding Gamora — destroy the opposition to the pounding tones of the Beastie Boys' "No Sleep 'Til Brooklyn".
Quill orders Knowhere to close so that Cosmo the Spacedog — who has telekinesis — can form an airtight bridge and all the alien kids can jump onboard. Meanwhile, Rocket goes looking for the High Evolutionary, and encounters a bunch of Earth animals — including infant raccoons — that are imprisoned for further experimentation. Here, the High Evolutionary encounters him. He thinks it's a one-on-one fight... But he's facing the Guardians of the Galaxy, and the entire team piles on, with Gamora landing the final blow. Rocket then orders Knowhere to hold position so that the Guardians can evacuate the animals as well. At the end, only Peter is left on the Arête as the two ships drift apart. He improvises a solution to propel himself across the void of space... but hits a piece of debris, stranding him in vacuum. His rescuer: Adam Warlock. Peter lives, and the Guardians and the staff of Knowhere pile on for a group hug (with Adam awkwardly joining in on the far end).
In the denouement, Groot tells Gamora that her ride back to the Ravagers has arrived — and Gamora understands him for the first time, a reminder of the Family of Choice she once shared. Peter, meanwhile, resigns from the Guardians, declaring it's time for him to go back to Earth and continue the arrested development that began when he was kidnapped as an eight-year-old. Mantis decides to split off as well, with the Abilisks to protect her; Nebula also bows out, choosing instead to take care of the (many) children rescued from the High Evolutionary, and suggests that Drax — the born father — come with her. When Rocket protests that he's been left all alone, Peter formally cedes the leadership of the group to him — recognizing Rocket as The Protagonist of the film, and indeed the franchise as a whole. And, even though the Family of Choice is splitting up for good — both Bautista and Saldaña have announced that they have no plans to return to their roles, and Pratt is skeptical about doing so without writer-director James Gunn — we are reminded of what we shared when the audience, for the first time, understands Groot's Pokémon Speak:
- Groot: I love you guys.
Peter returns to Earth and is welcomed with open arms by his grandfather. Gamora returns to her new family with the Ravagers. Mantis sets off on her own, while Rocket, Nebula, Drax and Groot have a Dance Party Ending with the kids. And, in The Stinger, the next incarnation of the Guardians of the Galaxy — Groot, Kraglin, Phyla (one of the kids the High Evolutionary engineered), Adam Warlock, Blurp, and, as The Captain, Rocket Raccoon — take on a new mission.
