In Gotham City, the vigilante Batman defuses a hostage situation orchestrated by a criminal known as Two-Face—formerly district attorney Harvey Dent, who was disfigured with acid by mobster Sal Maroni, which Batman failed to prevent—but Two-Face escapes. Edward Nygma, an eccentric researcher at Wayne Enterprises, approaches his employer, Bruce Wayne—secretly Batman—with an invention that can beam television signals into a person's brain. Bruce rejects the device, concerned the technology could manipulate minds. After killing his supervisor and staging the death as a suicide, Nygma resigns and plots revenge against Bruce, obsessively sending him riddles; as a favor to Bruce, criminal psychologist Chase Meridian diagnoses that his stalker is psychotic.