After half of all life is snapped away by Thanos, the Avengers are left scattered and divided. Now with a way to reverse the damage, the Avengers and their allies must assemble once more and learn to put differences aside in order to work together and set things right. Along the way, the Avengers realize that sacrifices must be made as they prepare for the ultimate final showdown with Thanos, which will result in the heroes fighting the biggest battle they have ever faced.
—Blazer346
Avengers: Endgame picks up after the events of Avengers: Infinity War, which saw the Avengers divided and defeated. Thanos won the day and used the Infinity Stones to snap away half of all life in the universe. Only the original Avengers - Iron Man, Captain America, Thor, Hulk, Black Widow, and Hawkeye remain, along with some key allies like War Machine, Ant-Man, Rocket Raccoon, Nebula, and Captain Marvel. Each of the survivors deals with the fallout from Thanos' decimation in different ways, but when an opportunity presents itself to potentially save those who vanished, they all come together and set out to defeat Thanos, once and for all.
—Santhosh