It's been a long night for Kristen McKay (LIV TYLER) and James Hoyt (SCOTT SPEEDMAN). Arriving at his father's empty summer home following another couple's wedding, James thought he had everything figured out and arranged the place for a romantic setting, complete with champagne and roses everywhere. Yet, when he popped the big question, Kristen turned him down, leaving both of them in a confused funk.
Calling off their planned road trip together, the two console each other over a future marriage that's not to be. But just when that leads to some fooling around, they're interrupted by a knock at the door. At 4 a.m., by a young woman looking for someone who doesn't live there.
Kristen and James aren't sure what to make of that, but figure it's just a fluke, and thus James heads off to replenish Kristen's cigarette supply. While he's gone, however, the young woman returns and again knocks and then bangs on the door. Kristen is unnerved by this, but that gets worse when she believes that someone's in the house. Armed with a kitchen knife, she retreats to a bedroom for safety, only to realize the most recent sounds were made by James who's returned.
Although he doesn't initially believe her story, a series of events soon change his mind. From that point on, the unhappy couple quickly realize that their failed romance is the least of their worries as a hooded man and two mask-wearing women proceed to terrorize them in that house.