At long last, it's Harley Quinn and The Joker, face-to-face! Harley's got an endangered friend to save, but there's just one problem: she's got to get through Arkham Asylum first! Unsurprisingly, Harley's not eager to set foot in the site of some of her darkest hours...and she definitely isn't ready to face a certain someone who's laughing at the end of a dark hallway. The life of Harley's new love, Mason Macabre, is in the Joker's hands...but can he or Harley survive another round of The Joker's twisted mind games?