Batman comes to Vanity...hot on the trail of the Joker. And the trap the Dark Knight encounters there may prove to be his death and that of Vanity's resident hero, Aztek.
Fixit, the technologist to super-villains, is approached by a villain named Heatsnap. Heatsnap is after a gun that can shoot both hot and cold, but his(?) purchase is interrupted by Aztek and Batman. The duo discovered that Fixit supplied the Joker with his mind-control crickets last issue, and are now here to shut him down. They fight Heatsnap, and defeat him(?) and Fixit. Batman discovers a lead on the Joker, but also discovers that Heatsnap was once the villains Coldsnap and Heatstroke. Lovers that could not touch, they underwent an experimental procedure that accidentally merged them into one being.
Finding a children’s book that Joker left behind, Batman and Joker continue their search for the Joker’s next step of his plan. All the while, Batman investigates more about Aztek. He finds out from Alfred that his father, Thomas Wayne, had been approached by the Q Foundation. He also finds out that Clarence Vale, founder of Vanity, created the city modeled after some occult architecture. As he hangs up with Alfred, Batman discovers that he has lost control of the Batmobile.
Aztek checks in on Vanity City P.D. Chief Perrier, who is under the influence of one of Joker’s crickets. Aztek finds out that the Joker’s master plan involves a blimp over Vanity, which holds his Joker Serum and will spew it all over the city in 15 minutes. Meanwhile, Batman finds out that a Joker electronic virus is infiltrating the various systems all over Vanity City.
Batman uses the Batmobile’s computer systems to purge the electronic virus, while Aztek destroys the blimp before it can explode. At St. Bartholomew’s Hospital, the doctors have created an anti-virus to the Joker Serum. With the Joker’s plans thwarted, Aztek returns to St. Bartholomew’s, where he collapses in Julia Frostick’s office.