Ultron has won the war. After launching a devastating attack against humanity, the artificial intelligence now controls much of the world, while the survivors hide among the ruins. The Avengers and the remaining heroes still able to fight desperately search for a way to reverse the situation. When Wolverine proposes changing the past to prevent Ultron from ever being created, the group becomes divided over the consequences of such a decision. Their attempt to save the future leads them into a dangerous manipulation of time, where every change risks creating an even more unstable reality.