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 (Matt 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 plans to confront Eric about dodging the draft after the boys and their respective girlfriends, Bailey (Diora Baird) and Chrissie (Jordana Brewster), head across Texas for a final fling of serious fun. Soon after their journey begins, the foursome are spooked by a menacing pair of bikers, who causes a car accident and then attempts to rob the injured trio. However, Sheriff Hoyt (R. Lee Ermey) arrives and turns the tables on their would-be assassin, before ordering Dean, Eric and Bailey into the back of the patrol car.
Unbeknownst to Chrissie, who watches everything happen from hiding, Hoyt is headed to the Hewitt family home where a man named Thomas (Andrew Bryniarski) is being groomed to become the terrifying monster known as Leatherface, and the rest of the Hewitt clan await. Chrissie 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 the Hewitt family upon the people she loves, she realizes she is their only hope of survival.