We've all heard the stories, seen the movies, imagined what would happen if we could start something over, change the past to how we wish it had occurred. But what if it is harder than we think to change the past? What if things happened back then how they had to happen, not because of random chance, but because it couldn't happen any other way? If faced with an opportunity to witness and relive the past, how would we cope with the timeline if we were powerless to change it?