Five college studentsDana (Kristen Connolly), Curt (Chris Hemsworth), Jules (Anna Hutchison), Marty (Fran Kranz) and Holden (Jesse Williams)go for a vacation at a remote cabin in the woods. Unknowingly, they are watched by two sophisticated technicians: Richard Sitterson (Richard Jenkins) and Steve Hadley (Bradley Whitford).
By using environmental controls and releasing mood-altering drugs into the air, the technicians are able to manipulate the environment the students are in. The manipulation reduces the students' intelligence and enhances their libido and lack of caution. Eventually, one by one, the students are manipulated into disobeying instructions so they can be "punished."