When a vampire serial killer sends Anita Blake a grisly souvenir from Las Vegas, she has to warn Sin City’s local authorities what they’re dealing with. Only it’s worse than she thought. Ten officers and one executioner have been slain—paranormal style. Anita heads to Vegas, where’s she’s joined by three other federal marshals, including the ruthless Edward. It’s a good thing he always has her back, because when she gets close to the bodies, Anita senses “tiger” too strongly to ignore it. The weretigers are very powerful in Las Vegas, which means the odds of her rubbing someone important the wrong way just got a lot higher.

When Anita receives a decapitated head in the mail, she must go to Las Vegas, Nevada to face a vampire serial killer. Vittorio (the master vampire serial killer that got away in Incubus Dreams) has sent this package to bait her, so she heads to Vegas to help out the local authorities and warn them on what they are about to face. Before she arrives in Sin City, Anita discovers that the slaughter has already began. And, Vittorio has also set a personal trap for Anita for reasons she does not yet understand. Federal Marshals Edward, Olaf, and Bernardo have all been called in to assist on the case.

Anita also has trouble on the work front. Someone has been trashing Anita's reputation and the local authorities seem to have a problem trusting Anita. Living with a vampire might have something to do with it. Can Anita help with the case and regain the trust she once had?

The local weretiger clan makes an appearance as well and Queen Bibi challenges Anita.

To make matters worse, Anita receives a surprise visit from the Mother of All Darkness. Mommy Noir finally reveals her plan for Anita and it is not good. It would mean the destruction of everything Anita holds dear.