In this groundbreaking, painted graphic novel, the inmates of Arkham Asylum have taken over Gothams detention center for the criminally insane on April Fools Day, demanding Batman in exchange for their hostages.Accepting their demented challenge, Batman is forced to live and endure the personal hells of the Joker, Scarecrow, Poison Ivy, Two-Face and many other sworn enemies in order to save the innocents and retake the prison.During his run through this absurd gauntlet, the Dark Knights own sanity is placed in jeopardy.This special anniversary edition trade paperback also reproduces the original script with annotations by Morrison and editor Karen Berger.