Former DA Harvey Two-Face blames Batman for a courtroom accident which left one side of his face hidously disfigured. Having now become a criminal mastermind, he seeks to humiliate and entrap the Caped Crusader at every turn, but is constantly thwarted. Meanwhile, in the laboratories of Wayne Enterprises, nerdish Edward Nygma has developed a device which channels other people's brainwaves into the mind of the wearer, but Bruce Wayne rejects the idea as inhumane. Nygma surreptiously tries out the device on his reluctant team manager, only to end up frying his own brain and flipping his sanity. He vows vengeance against Bruce Wayne, with whom he has always been obsessed. Beautiful psychologist Meridian Chase is also obsessed: with Batman, but is making do in the meantime by being squired around town by Bruce Wayne, who is besotten with her. One night they go to see the Grayson family perform at the circus when Two-Face and his thugs burst in and threaten to blow up the Big Top. Wayne battles the thugs, helped by the Graysons. Two-Face eventually retreats, but not before having caused the deaths of three of the Grayson family. Bruce Wayne adopts the orphaned survivor, Dick Grayson. At the Wayne mansion, Dick stumbles on the Batcave and discovers Wayne's big secret. He insists they become crime-busting partners but Wayne refuses. Meanwhile, Nygma has metamorphisised into the master criminal, The Riddler, and approaches Two-Face with a scheme to out Batman's real life identity: posing as suave businessman E. Nygma, he will invite all the town worthies - including Bruce Wayne - to the launch of his new contraption, get all of them to try it and from their brainwaves discover who really is Batman. During the evening, an impatient Two-Face brings in his thugs, once more to be thwarted by Batman, once again helped by Dick. But the Riddler has figured out who Batman really is, destroys the Batcave and kidnaps Meridian. Batman agrees Dick can join him, as Robin, the Boy Wonder.