Two romantic couples, consisting of four teenagers, decide to spend a weekend together located in a remote cabin found in the woods. An unseen force stalks and watches the group without their knowledge. Ellen and her boyfriend Bruce enter the woods to have a picnic lunch. The other couple, Scotty and Shelly, remain at the cabin playing Monopoly (game) to pass time. During their lunch, Bruce announces to Ellen that they're camping on an Mound builder (people). Ellen is concerned, but Bruce assures her that they will be fine as long as they don't disturb the graves of the dead. Bruce then explores the area and discovers an ancient dagger belonging to the Indians. Ignoring his own advice, he takes the dagger with him.