Thanos and his children – Corvus Glaive, Proxima Midnight, Ebony Maw and Cull Obsidian – destroy planet Xandar to retrieve the Power Stone and begin assembling the Infinity Gauntlet.
Meanwhile, on Earth, The Avengers are disbanded. Captain America, Black Widow and Falcon are wanted vigilantes, Scarlet Witch and Vision are on a romantic getaway in Scotland, Hawkeye and Ant-Man went off the grid, and Iron Man is developing new technologies to protect Earth from another alien invasion.
Thanos attacks the Asgardians’ ship and defeats Thor, who is cast out into space. Loki uses the Space Stone to teleport Bruce Banner to the Sanctum Sanctorum in New York City to find help and then surrenders it to Thanos in exchange for the Asgardians’ lives, becoming Thanos’ advisor. Thor is later found by the Guardians of the Galaxy, who are investigating Xandar’s destruction.
Rocket and Groot accompany Thor to the kingdom of Dwarf King Eitri, who forged the Infinity Gauntlet for Thanos, and then had his hands cut off Eitri’s hands so as to not interfere with Thanos’ plans. Thor builds a new weapon, the Stormbreaker, which can damage the Infinity Gauntlet.
Meanwhile, Banner is found by Doctor Strange, who contacts Iron Man. Upon learning of the impending invasion, Iron Man begrudgingly asks Captain America for help. Spider-Man joins Iron Man and Doctor Strange as they battle Ebony Maw and Cull Obsidian, who steal the Time Stone from Strange. The trio pursues them to Thanos’ warship, which leaves Earth.
Meanwhile, Scarlet Witch and Vision are ambushed in Scotland by Corvus Glaive and Proxima Midnight, but rescued by Captain America, who takes them to Wakanda so Black Panther and his forces can protect the Vision. Black Panther's sister Shuri extracts the Mind Gem from Vision's forehead.