Barry (Ezra Miller) uses his superpowers to travel back in time to change history and save his family, but inadvertently changes the future. In this new future, General Zod (Michael Shannon) has returned and is threatening to destroy the world. Barry is alone unless he can convince a very different, retired Batman (Michael Keaton) to come out of retirement and save the imprisoned Kryptonians - though this isn't the Superman he knows. Ultimately, Barry's only hope of saving the world he's in and returning to the future he knows is to speed for his destiny. But even if Barry makes the ultimate sacrifice... can he really set the entire universe right?