The story begins with Barbara Gordon, who is operating as Batgirl, assisting Batman in his fight against crime. She finds herself entangled in a dangerous chase with a criminal named Paris Franz, who develops an unhealthy obsession with her. After a confrontation that puts her life at risk, Barbara decides to reconsider her role as Batgirl, to the concern of both Batman and her father, Commissioner Gordon. Meanwhile, the Joker escapes from Arkham Asylum with a terrifying plan targeting Commissioner Gordon, intending to drive him insane.

The Joker's scheme is intertwined with flashbacks revealing his traumatic past and transformation into the Clown Prince of Crime. Seeking to prove that one bad day can push anyone into madness, the Joker kidnaps Commissioner Gordon and subjects him to psychological and physical torment. As Batman races against time to rescue Gordon and stop the Joker, tensions rise and the boundaries between hero and villain blur. The narrative explores the complex relationship between Batman and the Joker, delving into themes of sanity, morality, and the fine line separating the two adversaries.