“DOUBLE BATMAN VS. DOUBLE X!” Simon Ecks escapes from the sanitarium he was locked in with his memory restored. Ecks decides to develop another duplicator device and becomes Dr. Double X once again. He matches wits with Batman again, although this time, Batman is able to defeat him by generating an energy duplicate of himself with Ecks’ machine. Baman fights Ecks while their respective duplicates fight each other.

In order to combat Dr. X and his energy duplicate Dr. Double X, Batman subjects himself to a process that creates a Double Batman.