There's an old myth that haunts the seemingly perfect small town of Roosevelt: If you have sex too young, you'll contract the 'bug', a virus that literally turns you into a 'monster' from your worst nightmares. Absurd, right? That's what Chris always assumed, until, after one reckless night at the beginning of senior year, she finds herself infected. Now she'll be cast out to the woods to live with the other infected, where a chilling, new threat emerges: a serial killer who's hunting them one by one.