Realities collide in THE FLASH when Barry uses his superpowers to turn back time and alter his past. But his efforts to save his family are not without consequences for the future, and Barry finds himself trapped in a reality where General Zod is back, threatening to wipe out the planet, and where superheroes have gone. Unless Barry can pull a much-changed Batman out of retirement and come to the aid of an incarcerated Kryptonian, who isn’t necessarily the one he’s looking for. Barry then engages in a terrible race against time to protect the world he is in and find the future he knows. But will his ultimate sacrifice be enough to save the universe?