Avengers: Endgame

Five years after losing, the survivors get one attempt to undo it.

The first hour is the unusual part: a film about defeat, grief and the shapes people take when they stop trying. The plan does not begin until the survivors have been shown living with having failed.

It is the end of the run that started in 2008, and it assumes all of it. Watching it without the films before it is technically possible and mostly pointless.