It has all been building to this. 10 years of the Marvel Cinematic Universe has been leading to Avengers: Infinity War . From Google: "Iron Man ( Robert Downey Jr. ), Thor ( Chris Hemsworth ), the Hulk ( Mark Ruffalo ) and the rest of the Avengers unite to battle their most powerful enemy yet -- the evil Thanos ( Josh Brolin ). On a mission to collect all six Infinity Stones, Thanos plans to use the artifacts to inflict his twisted will on reality. The fate of the planet and existence itself has never been more uncertain as everything the Avengers have fought for has led up to this moment."