Sam Maddox is a troubled girl whose father committed suicide, and who has earned a reputation at her high school for being a bit of a "slut." When Sam begins seeing brilliant, MIT-bound Henry Sinclair, these opposites really attract. But although Sam doesn't realize it yet, Henry is in the grip of an insane romantic obsession, and he will kill anyone who tries to put an end to his star-crossed - and increasingly deadly - romance.