Gotham City Sirens is an American comic book series that was written by Paul Dini with art by Guillem March and published by DC Comics. The term Gotham City Sirens refers to three of the most popular female villains inhabiting Gotham City: Catwoman, Harley Quinn, and Poison Ivy. The first issue of the series was released in June 2009, as a part of the Batman: Reborn relaunch of DC's entire line of comic book titles featuring the superhero Batman. Plot Setting Shortly after the events of the Heart of Hush, Batman R.I.P., Final Crisis, and Battle for the Cowl storylines, Hush cuts out Catwoman's heart, Batman retrieves it, and Zatanna heals her. Catwoman gets her revenge by stealing all of Hush's money and giving it to Gotham City's female criminals, Harley Quinn and Poison Ivy, as well as Holly Robinson. Bruce Wayne is thought to be dead and is replaced by Dick Grayson. "Union" When Catwoman fights a new villain named "Boneblaster", it is revealed she still has physical limitations from her ordeal in "Heart of Hush" and is nearly easily beaten by the two-bit thug. However, Poison Ivy arrives to save Catwoman and offers her to return to her new hideout, which is actually the hideout of the Riddler, whom Poison Ivy has seduced and drugged. Catwoman discovers Harley Quinn is also living with them, and proposes that the three women join together to protect one another as a team, but first Harley Quinn and Poison Ivy want to know who Batman really is. When Poison Ivy uses a truth serum powder derived from plants, Catwoman reveals that she cannot because Talia, Ra's al Ghul's daughter and leader of the League of Assassins, used mind control techniques to prevent Catwoman from ever forcefully revealing his identity as Bruce Wayne. Talia taught Catwoman a meditation technique so that any sort of mind-control, such as Ivy's spores, will not affect her. Harley Quinn leaves Poison Ivy's hideout, while Grayson, who is acting as Batman, and the "reformed" Riddler solve a coinciding case that leads to Quinn encountering Bruce Wayne. Unbeknownst to her, he is actually Hush, who had reconstructed his face to be that of Wayne so he could control Wayne Enterprises. Hush plans to kill Quinn, but when footage of the two together reaches Joker, he decides to kill Harley since he cannot have her. The Joker is revealed to