A nerdy high school senior transforms into a vampire vixen who's unaware that her hunky date for prom is the slayer sent to destroy her.

Morgan Taylor-Jackson can't wait for high school to end. In six months she leaves for UCLA and says goodbye to La Jolla, California and her parents' messy divorce. But when Morgan is bitten by a four-year-old boy, she becomes infected with a mysterious condition. Fever, insomnia, and a new bustline are only the beginning; Morgan morphs from nerd to bombshell.

As far as Van Xander is concerned, all vampires are evil, even the ones who reject human sacrifice and call themselves Puritans. When Helsing Incorporated sends Van to La Jolla to investigate the local coven, Morgan is his prime target. Pretending to be interested in her, Van asks Morgan out and puts her through a series of tests to determine her killer nature.

Morgan is thrilled to be dating a hot guy like Van and falls for him hard. As Van strings Morgan along, he grows increasingly guilty. Morgan is kind, compassionate, and a gooey romantic. Just as Van's mind begins to change, evil forces threaten everything. When prom night arrives, there are only two ways out of the ballroom: death or immortality.