The full story
Endgame opens in the immediate aftermath of the snap. Clint Barton watches his entire family dissolve into ash. Tony Stark drifts through space, starving, recording goodbye messages for Pepper. The remaining Avengers track Thanos to his farm, hoping to use the Stones to undo the snap, but he has already destroyed them. Thor decapitates him in a fit of rage. Everyone is still gone.
Five years pass.
The world has moved on. Half of all life is still gone. Steve runs support groups for survivors. Natasha coordinates global operations from Avengers HQ. Tony has retired, raising a daughter with Pepper. Thor has fallen into depression and substance abuse in New Asgard. Bruce has merged with Hulk, achieving balance as "Professor Hulk." Clint has become Ronin, executing criminals across the globe.
Then Scott Lang escapes the Quantum Realm. For him, only five hours passed. He brings an idea: the Quantum Realm could enable time travel. They could go back, collect the Infinity Stones from the past, and use them to bring everyone back.
Tony initially refuses—he has a daughter now and a life he would lose if they change the past. But the memory of Peter Parker gets to him, and he works through the night to crack the equation. He agrees to help.
The time heist involves multiple teams traveling to different points in history. New York 2012: Tony, Scott, Steve, and Bruce attempt to retrieve the Space, Mind, and Time Stones during the Battle of New York, but Loki escapes with the Tesseract. Tony and Steve go further back to 1970, where Tony retrieves the Tesseract and encounters his father. Asgard 2013: Thor retrieves the Aether and speaks with his mother. Vormir 2014: Natasha and Clint confront the reality that one of them must sacrifice themselves for the Soul Stone. Natasha chooses to die so Clint can live.
Morag 2014 goes wrong. Nebula's cybernetic implants sync with her past self's network. Past Thanos learns everything. He sends 2014 Nebula back disguised as present Nebula, and she opens a portal for his entire army.
But first, Bruce snaps everyone back. Five years of dust reverses. Trillions of lives restored.
Then Thanos's ship destroys Avengers HQ.
The final battle features the three original Avengers—Tony, Steve, and Thor—fighting Thanos together. Steve wields Mjolnir. Portals open, and everyone returns: T'Challa, Shuri, Okoye, the armies of Wakanda, Strange, Wong, the sorcerers, the Guardians, and Spider-Man. "Avengers... assemble."
Thanos obtains the gauntlet and prepares to snap again. Carol nearly stops him, but he uses the Power Stone to knock her away.
Tony makes the play. He grabs the Stones from the gauntlet, loads them into his own armor. "I am Iron Man." He snaps. Thanos's army dissolves. Thanos himself crumbles to dust.
Tony Stark dies in the arms of Pepper Potts, surrounded by the people he saved.
Steve returns the Stones to their proper timelines but does not come back to the present. He stayed in the past and lived the life he never had. Now an old man, he passes his shield to Sam Wilson.
Encore keeps going where the 2019 cut stopped. In the past, Steve and Peggy are dancing in their living room when someone knocks at the door. Steve steps out of sight and Peggy answers. On the porch is Loki in his TVA suit: the Loki of his own series, not the 2012 variant who escaped with the Tesseract earlier in the film. Peggy asks if she can help him. "No," he says, "but I can help you. Both of you." Steve steps out of the shadows to face him, and the screen cuts to black.
The first post-credits scene jumps forward to after Spider-Man: Brand New Day. Bruce Banner is recording a video log from a bunker two miles under an old military base, where he has sealed himself away after his first incident in over a decade, and explaining his gamma suppression experiments. The power flickers, and Doctor Doom speaks: "Mr. Banner. I'm here to collect you." Bruce starts to transform, the Hulk roars, and the camera falls. When it comes to rest, both of them are gone, leaving only green magical sigils on the floor.
The second is at the TVA. Mobius arrives for work to find Casey tracking an incursion between Earth-10005, the Fox X-Men universe, and Earth-1127: two Earths on a collision course, missiles flying between them. Then the alerts multiply until some 3,000 universes are colliding at once and Earths are being destroyed faster than the TVA can log them. O.B. says it out loud: "The multiverse is collapsing."
The last is the clanging. The 2019 credits ended on the sound of hammering on metal, a callback to Tony Stark building his first suit in a cave. Encore finally gives it a picture: Doctor Doom, at an anvil, forging his mask.