The Guardians of the Galaxy go to Planet X, Groot's Homeworld, to revive it with the world pod Warlock gave him. They find the planet is crawling with Symbiotes bonded to what remains of Groot's species. They run away, but not before a Symbiote bonds to Rocket. Gamora remembers the planet was where Thanos experimented on Symbiotes to weaponize them, using Gamora as his test subject. Thanos abandoned the project after he realized the Symbiotes could not be controlled. They free Rocket using Thanos' debonding device, and Rocket warns them that the other Symbiotes are all coming for the world pod. Gamora suggests they could use a "doomsday device" Thanos' left on the planet as a failsafe if the Symbiotes turned on him. Even though the other Guardians object, Groot reluctantly agrees to use the device rather than leave his homeworld to the Symbiotes. They're ambushed by the Symbiotes just as Rocket Raccoon activates Thanos' weapon. The Guardians try to escape, but their exit is blocked by a group of mysterious creatures. Star-Lord recognizes them as creatures that saved him from the Symbiotes earlier and tries to reason with them, only for one of the to apparently "eat" him. The creature instead bonds with Quill, and they help the Guardians fight off the Symbiotes. The creature bonded to Quill introduces himself and the other "good" Symbiotes as the Klyntar, members of a peaceful race than Thanos captured and distorted into the "feral" Symbiotes. Gamora, Drax and Rocket allow the remaining Klyntar to bond with them so they can escape the planet together. Groot eventually lets the last Klyntar bond with him when it is seriously wounded protecting him from the Symbiotes. Together, they fight their way to the Milano before Thanos' weapon blows up the planet. They retreat to the nearby Planet Y, where Groot can mourn the loss of his homeworld. Groot plants the world pod on Planet Y so his species can be reborn there, with the Klyntar serving as their guardians. Gamora notices what she thinks is a comet passing the planet, but the Klyntar bonded to Quill recognizes it as a fragment of Planet X covered in Symbiotes. The Guardians leave Planet X to stop the Symbiotes.