When an airplane transporting a bombing suspect and Schanke explodes, Nick becomes racked with guilt. He feels it should have been him on the plane and not Schanke. Nick turns in his badge, ready to move on to a new life. He decides to return when other police stations in the city start exploding.

Nick's discovery that Tracy's mystery man, Vachon is a vampire, complicates an already complicated situation. Luckily Vachon and Tracy's mutal attraction saves Tracy's life. However, Tracy's awareness of vampires, and Vachon's penchant for running from his responsibilities place them all in danger as the bomber plots to use Tracy in his next bombing.

When a serial rapist is ripped to shreds by a dog, Natalie suspects that something isn't quite right. Nick's investigations leads him to suspect a carouche, a lower form of vampire who typically feeds on vermin, may be behind the dog's behavior. When Nick finds the dog, he discovers that it is the devoted companion of a blind dispatcher. Now he must figure out how to protect the dispatcher (and everybody else) from her not-so-mortal dog.

A scientist is murdered and a lab rat escapes when industrial espionage goes awry. But far worse things begin to happen when the lab rat, infected with a newly engineered virus becomes Screed's next meal. Designed to combat HIV, the virus becomes lethal to vampires as it multiplies and intensifies each time they "feed". As the virus spreads rapidly through the vampire community, it infects Vachon, Nick, and LaCroix. Nick races agains time to find the killer - while Natalie struggles to find a cure.