Kelly Peterson and seven other high school students have enrolled in an intensive SAT course, to be held at a secluded cabin during Thanksgiving vacation. Tragedy strikes on the first night of their trip when Brian Lopez, Kelly's closest friend, drowns in a nearby lake. Brian's longtime (and possessive) girlfriend, Paula, had been with him, and claims he died from a struggle with an unknown assailant. When their teacher goes in search of help but doesn't return, the group is convinced that a madman must be stalking the area, waiting to pounce on his next victim.