One brother is learning to move on, while the other clings to the past. Two years after defeating Callaghan, Hiro and Baymax fall into an alternate timeline where Hiro had died instead of Tadashi. As Gogo, Honey, Fred, and Wasabi find a way to get Hiro back to his original timeline, Hiro searches for a way to help Tadashi move on. (Contains Anti-hero Tadashi)