It's open season on Harley Quinn when her explosive breakup with the Joker puts a big fat target on her back. Unprotected and on the run, Quinn faces the wrath of narcissistic crime boss Black Mask, his right-hand man Victor Zsasz, and every other thug in the city. But things soon even out for Harley when she becomes unexpected allies with three deadly women, namely Huntress, Black Canary and Renee Montoya.