After being accidentally dosed with chemicals, Barry Allen develops the gift of superhuman speed. As part of the Justice League, Barry has continued to explore the limits of his powers.
When Barry Allen arrives in an alternate 2013, he seeks out his friend and mentor Bruce Wayne, but the Bruce Wayne he finds in the Multiverse is completely different.
The alien Kara Zor-El has been hidden away from the world. It remains to be seen if Kara will have the strength to become the superhero the world needs: Supergirl.