In Gotham City, Batman defuses a hostage situation orchestrated by the criminal Two-Face, formerly district attorney Harvey Dent, who escapes. Flashbacks reveal that Dent was horribly disfigured with acid on one side of his face by mobster Sal Maroni, causing him to develop a split personality and swear vengeance against Batman for failing to prevent the incident. Edward Nygma, an eccentric researcher at Wayne Enterprises, approaches his employer, Bruce Wayne, to present an invention that can beam television signals directly into the brain, demanding immediate approval from Bruce. After killing his abusive supervisor and staging it as a suicide, Nygma resigns and plots revenge against Bruce, sending him riddles. Batman attends a circus with psychologist Chase Meridian, where Two-Face hijacks the event and threatens to detonate a bomb unless Batman reveals his identity. Dick Grayson, the youngest member of the Flying Graysons family of acrobats, prevents the bomb from killing anyone by throwing it into a river with the help of his family; however, Two-Face kills all of them except Dick in the process. Bruce invites the now-orphaned Dick to live at Wayne Manor as his ward, where he later discovers that Bruce is Batman. Nygma becomes the Riddler and teams up with Two-Face, committing a series of robberies to finance Nygma's new company and mass-produce his brainwave device dubbed the Box. As Batman pursues Two-Face and the Riddler, he visits Chase, who explains that she has fallen in love with Bruce, and reveals his secret identity to her. Having discovered Bruce's secret through the Box, on Halloween night, Two-Face and the Riddler destroy the Batcave, shoot Bruce, and abduct Chase. As Bruce recovers, he deduces that Nygma is the Riddler through clues he left in his riddles, while Chase is held prisoner in the Riddler's lair. Robin eventually defeats Two-Face but chooses to spare him, allowing Batman to rescue both when he sees the floor is an optical illusion. Two-Face corners them and flips his coin to decide their fate, but loses his balance after Batman throws multiple identical coins in the air, and falls to his death. Committed to Arkham Asylum, a now-delusional Nygma exclaims that he is Batman. Bruce, the real Batman, resumes his crusade with Robin as his partner.