Barry Allen awoke to a world he barely knew, but this is not a number one or parallel Earth. Something or someone caused a change in time to replace Barry's world with this one. And this new world is not a safe place.
Without the support of his powers or friends, Barry reaches out to Bruce's father, Thomas Wayne, the new Batman, who himself survived while his son died. They are now working together to restore the world. If they fail, they will never get out of this twisted, tragic world.