It's 1969. The conflict in Vietnam has exploded to immeasurable proportions, and 18-year-old Dean Hill's (Taylor Handley) number is up. Dean's brother Eric (Matthew Bomer), who has already seen his share of combat plans to take Dean to enlist in his beloved Marine Corps in hopes of keeping an eye on him rather than letting him take his chances at the local induction center.

But Dean's plans do not coincide with his older brother's. Instead, he plans to confront Eric about dodging the draft after the boys and their respective girlfriends, Baily (Diora Baird) and Chrissie (Jordana Brewster) head across Texas for a final fling of serious fun.

Soon after their journey begins, the spirited foursome are spooked by a menacing pair of bikers, Holden (Lee Tergesen) and his girlfriend, Alex (Cyia Batten). When Alex chases the group's jeep, propelling thim into a serious accident, Chrissie is thrown from the vehicle. As Alex attempts to rob the injured trio, Sheriff Hoyt (R. Lee Ermey) arrives on the scene and turns the tables on their would-be-assassin. While Chrissie hides in the nearby brush, she watches as the sheriff kills Alex in cold blood and then inexplicably taunts her friends before ordering them back into the back of the patrol car.

Unbeknownst to Chrissie, Hoyt is headed back to the Hewitt family home where Thomas, who is being groomed to become the terrifying monster known as Leatherface (Andrew Bryniarski), and the rest of the Hewitt clan await. In an effort to save her friends, she attempts to convince Holden to help her, but he is on a one-man rampage to avenge his girlfriend's death. As Chrissie witnesses the horrors inflicted by teh Hewitt family upon the people she loves, she realizes she is their only hope of survival.