The plot revolves around the Joker's attempt to drive Gotham Police Commissioner James Gordon insane. The story is interrupted by flashbacks to the Joker's life before he went insane. The comic reveals Alan Moore's speculation that psychologically "Batman and the Joker are mirror images of each other." Critic Jeff Klock stated that "both Batman and the Joker are products of the random and tragic events of 'one bad day.' Batman spends his life making sense out of random tragedy, while the Joker reflects on the absurdity of life and its random injustice."