In this movie, we follow along with Captain America as he travels through time to return the infinity stones to their respective places and we witness what made Cap decide to stay in the past. First, the Soul Stone is returned to the Red Skull in Vormir. Next, the Power Stone is returned to the hands of Starlord. The next stone, the Reality Stone is injected in Jane Foster and after a brief chat with Loki, the next time jump is to return the Space Stone. While returning the Space Stone Howard Stark catches up with his longtime friend. The Time Stone is returned to The Ancient One in New York and in the same day, Captain America returns the staff with the Vision Stone to his previous self. Not before having an honest conversation with his past self. And at last, the final decision made by Captain America, to stay back in the past and reunite with Peggy Carter.