"Gott würfelt nicht nur einmal" is about Kai Roth, a seemingly normal young man from Germany with the ability to reverse time. Unfortunately this ability comes at a cost. He doesn't know why he reversed time when he actually does it, because there can only be one time line at all times. So his past future doesn't exist anymore and he has to choose differently. Dominik Trapp, a boy with a deadly sick sister, finds out that Kai possesses these abilities and wants him to assist in saving his sister who is suffering from brain cancer. However, Kai can't and doesn't want to get caught up with Dominik. Therefore a game of cat and mouse ensues which leaves Dominik increasingly angry and he finally takes action.
