Harley Quinn...and that OTHER Harley Quinn, well, they got a problem. Somehow, someway, one of these Harley Quinns rode off in baby Kal-El's lil' rocket ship before he could leave Krypton way back whenever that was. She also, just MAYBE, distracted Barry Allen before that lightning bolt could hit, and don't get me started about all the other heroes. So now the whoooole DC Universe is all screwed up and these two HQs gotta figure out a way to put baby Supes back in the rocket before Krypton goes boom, Barry back in front of that lightning bolt, and stop that other Harley before...well, you get the picture. It's going to be bananas.