Avengers: Endgame sinopsis After Thanos activates the completed Infinity Gauntlet, Clint Barton’s family disintegrates, along with half of all life across the universe. Nebula and Tony Stark are stranded in space following their defeat by Thanos on Titan, but are returned to Earth by Carol Danvers and reunited with Natasha Romanoff, Bruce Banner, Steve Rogers, Rocket, Thor, and James Rhodes. The team formulates a plan to steal the Infinity Stones back from Thanos and use them to reverse his actions, but learn upon finding him that he had used the stones a second time to destroy them, preventing their further use. In anger, Thor cuts off Thanos’s head.
Five years later, Scott Lang escapes from the quantum realm to discover that his daughter Cassie is now a teenager and that Hope van Dyne, along with half of the population, has disappeared in the snap. Rogers has been leading grief counseling sessions for survivors still struggling with the effects of the snap, while Romanoff is tirelessly keeping watch over both Earth and the rest of the universe with the help of Rhodes, Danvers, Okoye, Rocket, and Nebula. Lang goes to Romanoff and Rogers, and explains that while five years had passed for them, only five hours had passed for him in the quantum realm. The three go to Stark, who is now raising a child with Pepper Potts, and explain their theory that the quantum realm can be used to go back in time and steal the Infinity Stones before Thanos is able to collect them. Stark initially rejects their proposal with concern about risking his family and the peace he has found, but after reflecting upon the loss of Peter Parker decides to test theoretical models that would work with Lang’s quantum tunnel, eventually finding one that works.
With Stark now on board with the plan, the remaining Avengers set out to reassemble their team. Bruce Banner has now embraced the Hulk as a part of him, and has melded his own consciousness and the Hulk’s together into one. Romanoff, after hearing reports from Rhodes of an assassin that operates with similar methods to Barton, goes the Japan to track him down. Barton, consumed with grief after the loss of his family, has been operating under the mantle “Ronin” while brutally massacring cartels and gangs in order to try and improve the world that’s still left. After some convincing from Natasha, he agrees to rejoin the team in order to try and bring his family back. Banner and Rocket go to the small town of New Asgard, where Valkyrie and the last survivors of Asgard have settled. They there find Thor, who has become overwhelmed by guilt over not killing Thanos the first time, in Wakanda. Thor has become majorly overweight, his hair and beard are overgrown, and he spends his free time eating junk food, getting drunk, and playing Fortnite with his friends Korg and Miek. Thor begrudgingly agrees to return to the Avengers after some convincing from Rocket and Banner.