Spoilers ahead for Avengers: Endgame. Time travel is a bitch of a narrative device. Like a wild horse, it'll buck off any and all comers, no matter how well they think they have the idea buttoned down. At first glance, such appears to be the case again in Avengers: Endgame. By the end of the story, too many things have gone wrong, too many moments in the past have been driven directly off the rails. There is no way the timeline is an intact Mobius Strip. This is no Kate And Leopold where the past and the future happen …