Avengers: Endgame's Most Confusing Plot Holes EXPLAINED

1. Cap Finally Makes Everything Okay

Endgame goes to great lengths spelling out that there are only so many chances to get everything right ("one round trip each and two practice runs" using the time machine), but Cap picks up more Pym Particle phials when he's back in the 1970s' SHIELD/Hydra base.

We see Cap pick up 4 phials in a set (and these are used to keep the main mission going), but there are two more sets that he could've also nabbed, for his final mission to restore the Stones.

Using the same theory we've had this whole time (that only the Avengers we're watching matter), Cap isn't visiting a number of realities to restore order, but points along the "main" timeline instead. By dropping in at key points in the established canon, he either prevents Loki from escaping by restoring the Space Stone's original position in the 70s, or Loki still escapes into his own TV show, only for events we haven't seen yet to return the Tesseract before Thor: The Dark World.

Either way, Cap is all about making a life for himself and Peggy, in the background of every other movie's events.

Cap is the only character who manages to loop back on his own timeline, and that's likely down to setting the last Infinity Stone in place, then remaining in the physical space he was left in, opting to miss his "window" to return to the present. The Tesseract is the "oldest" Infinity Stone we saw in the MCU, and it makes sense Cap would place it back into Howard Stark's storage last, back in the early 1940s.

There was always one main timeline; our MCU movie timeline, with all these events as they always were.

Cap needed to restore order by placing the stones back in the right place, and once that was done, he could live a long, happy life with Peggy.