In a possible future decades from now, an aging Bruce Wayne helps his successor Terry McGinnis (aka Batman Beyond) travel back in time to prevent a highly advanced A.I. from taking over society. Terry successfully makes the trip, but Bruce gets critically injured in the process and is left behind. Enemy forces quickly take Bruce and merge him with The Joker, whom they previously captured and have locked away combining the two in a twisted act that makes Super Hero one with Super-Villian Together, they become a deadly, cybernetic soldier whose singular mission is to destroy Batman Beyond before he can complete his mission and return home.