In one of of the many Kamen Rider worlds, Y/n, is a normal young man, until his homeworld was destroyed. But just when he was about to die, he was saved by a cloaked man in a time mazine. The man told Y/n that there's a way to save his world from being destroyed. He must travel through his timeline and other worlds to collect the ridewatches and become Kamen Rider Zi-O. However, unlike the original Zi-O, this story may find Y/n a little bit of an anti-hero, as his quest is to not collect the original ridewatches, but the ridewatches from all 19 dark riders.