Avengers: Endgame - Mysteries Answered

11. The Quantum Realm's Importance

Before fans even knew what Endgame was called, they knew that the Quantum Realm was going to be an essential part of the story. Not only did its huge focus in Ant-Man and The Wasp clue them in, but the Russo Brothers weren't shy in telling everyone that it would, in some way, be the key to the new movie's narrative.

The hows and whys were always up in the air though, and while plenty of people pieced together that it would be involved in time travel somehow, it was a mystery how that would actually work and what the ultimate goal would be.

It turns out that the Quantum Realm was indeed the key to Endgame, as the entire plot is built around it facilitating the Avengers' jump back in time in order to grab the Infinity Stones and re-snap everyone back into existence. Scott Lang is the only person who knows its potential, and as soon as he escapes he goes straight to Stark and Banner, who help him refine the science to create an actual time machine.