How Loki Fixes Avengers Endgame’s Biggest Plot Hole

How Did We Get Here?

In a supremely ballsy move from one of the MCU's most confident filmic duos, Anthony and Joe Russo essentially invented or at least spotlighted a new genre for Endgame - the "time heist".

Building an entire movie around the idea of our heroes travelling back through time to find enough Infinity Stones from different points in the MCU's past, it worked incredibly on a meta-narrative level too, letting those who'd been along for the ride take a sizeable trip down memory lane.

The rules were established that taking an Infinity Stone "out of time" to use it in the present IS allowed, if you then make a point of returning it. The reason given from Tilda Swinton's The Ancient One was that Earth needs these stones to defend against "the forces of darkness" that could manifest, and they simply can't be removed altogether.

Come the close of the film, Thanos is defeated and Captain America's last mission - with the help of some Pym Particles - is to return the stones, re-solidify the timeline, and emerge back in the present.

We watch Cap disappear through the time machine, and next we see him... a good 60-70 years have passed off-screen, leaving Steve a notably older man, now sitting peacefully on a park bench.

His 100+ year-old age isn't too big a problem - we can chalk that up to the Super Soldier Serum, after all - but the question of HOW Cap got back to that bench in the first place, appeared to break everything.