Varsity swimmer Ben Cronin (Bradford) appears to be on the fast track to success. A pending scholarship to Stanford. An adoring girlfriend. A cool truck. Then an innocent encounter over a jammed locker triggers unwise meetings with a new student, Madison Bell (Christensen). Late at night they visit the school pool where Madison initiates sex (there’s no doubt what’s going on below the water line). Ben shrugs it off as a one-time mistake, but quickly realizes he’s in over his head. Madison keeps turning up. And while he tries to keep his girlfriend from learning of the tryst, it gets increasingly difficult when the bitter "other woman" starts making waves in his life.

Madison isn’t merely an annoyance; she’s a soulless killer who shoots and bludgeons people to death (most violent confrontations happen off-screen). She tries to poison, drown and stab others who get in her way. Profanities, alcohol and cigarette smoking add to the troublesome content.