Two romantic couples, consisting of four teenagers, decide to spend a weekend together at a remote cabin tucked away in the woods. An unseen force stalks and watches the group without their knowledge, casting a quiet, uneasy shadow over their plans.
Ellen and her boyfriend Bruce head into the woods for a picnic lunch, while the other couple, Scotty and Shelly, stay back at the cabin and pass the time with a game of Monopoly. During their meal, Bruce reveals they’re camping on an Indian burial ground. Ellen grows uneasy, but Bruce tries to reassure her, insisting they’ll be fine as long as they don’t disturb the graves. Before they leave, Bruce wanders off and discovers an ancient dagger belonging to the Native Americans, and, ignoring his own warning, he pockets the weapon.
After lunch, Ellen naps. When she wakes, Bruce is missing, and she ventures into the woods to search for him. Her fear intensifies as she comes upon Bruce’s body, horribly mutilated with knife wounds. A demonic presence lurks in the trees, and Ellen bolts back toward the cabin as the invisible force closes in on her.
Back at the cabin, Ellen tells her friends that Bruce has been murdered, but Scotty dismisses the claim as a joke and goes to look for Bruce himself. Shelly and Ellen grow anxious as Scotty fails to return promptly. Shelly decides to join the search, but a possessed Bruce attacks and strangles her, stabbing her neck with the dagger he found, moaning, > Join us.
Ellen encounters her possessed friend and flees to another room, arming herself with knives for protection. Something tries to enter the room, and Ellen lashes out blindly, fatally stabbing Scotty who had just returned to the cabin. The possessed Bruce then lunges at Ellen, but she manages to trap him outside, slashing his hand several times in the process. The bleeding Scotty urges Ellen to look in the cellar for the gun they brought along. Down the stairs she trips on a broken step and injures herself; she finds the gun and returns to the upstairs only to discover Scotty has been stabbed to death.
The demonic Bruce attacks again, and Ellen fights back, severing his hand with the dagger. She attempts to flee, but the assault continues, leaving her battered and terrified. In a desperate move, Ellen grasps Bruce’s mutilated hand and, wielding the dagger, delivers a decisive stab. Blood erupts as Bruce collapses, seemingly still and then reawakening his threat. She finishes the struggle by using an axe to mutilate Bruce’s body, chopping off nearly every limb as she trembles, overwhelmed by what she has seen.
The camera lingers on Ellen as she mutters to herself, shaken and haunted by the night’s events. Then the corpse of Scotty suddenly rises and turns toward the traumatized survivor, leaving her fate uncertain as the screen cuts to black.
