Barry Allen awakens in a reality completely different from the one he knows: he no longer has his powers, his mother is still alive, and the world is on the brink of destruction. In this alternate timeline, Thomas Wayne has become Batman, Superman never emerged as a hero, and a war between Wonder Woman and Aquaman threatens to destroy the planet. Convinced that history has been altered, Barry tries to regain his speed and understand the origin of this new reality. His investigation forces him to confront the consequences of his own choices and decide how far he is willing to go to restore the proper course of time.