An unusual bolt of lightning rips through the Gotham night, striking the ground and leaving a strange purple dimensional portal in its place. In pursuit of Harley Quinn, who casually crosses the threshold of the portal, Batman finds himself thrust into it as well. With amnesia, he wakes up in a world he doesn't know and finds himself under attack from all sides. Time is running out, as a destructive purple force field seems to be closing in on him and his opponents. He must quickly build his new life in this strange universe and try to find his bearings.