After being booted out of the Joker's service, Harley Quinn forms a partnership with Poison Ivy. By day, they're house mates and best pals, by night, they're a deadly duo, billed 'The New Queens of Crime' by the Gotham tabloids. The Joker has a fit when he hears of their "Thelma and Louise"-style crime spree, and sets out to get Harley (and more important, the loot she stole) back. Batman has also figured out where the girls are, and both he and the Joker arrive at Ivy's hideout (a model house built over a toxic waste dump) to have it out with them. In an explosive battle Batman takes out the Joker and his men, but a surprise assist from Officer Montoya helps the Dark Knight finally collar Harley and Ivy.