On May 22, 1994, four teenagers—Barry, Heather, Jenny, and Sean—attend their school's prom in rural Texas. When Heather discovers Barry cheating on her with another girl, she storms out, followed closely by Barry, who tries to explain himself as they drive away in his car. Their argument is interrupted by Jenny and Sean, who are hiding in the backseat, smoking marijuana. Heather takes a detour off the freeway, and while distracted, collides with another motorist, who passes out in the ensuing confusion. Jenny, Heather, and Barry leave Sean to look after the unconscious motorist while they search for help.
They stop at an office trailer, where they meet Darla, an insurance agent, who promises to call her boyfriend, a tow truck driver named Vilmer. They leave the office and begin heading back towards the wreck, only for Heather and Barry to become separated from Jenny in the darkness. Vilmer soon shows up at the scene of the wreck, killing the motorist, before chasing Sean in his truck and backing over him repeatedly.
Meanwhile, Heather and Barry discover an old farmhouse in the woods. As Barry looks around, Heather is attacked by Leatherface on the porch swing and subsequently forced into a meat locker inside the house. One of Vilmer and Leatherface's family members, W. E., finds Barry and holds him at gunpoint before forcing him inside. Barry tricks W. E. and locks him out but while using the bathroom, Barry discovers a corpse in the bathtub. He is then killed by Leatherface with a sledgehammer. After killing Barry, Leatherface impales Heather on a meat hook.
Jenny returns to the scene of the wreck, where she is met by Vilmer, who offers her a ride. She accepts, only for Vilmer to threaten her, before showing her the bodies of Sean and the motorist hanging in the truck bed. Jenny jumps out of the truck and runs into the woods. She is soon attacked by Leatherface, resulting in a lengthy chase through the farmhouse, where she finds several preserved corpses in an upstairs bedroom. After leaping through an upstairs window, Jenny manages to flee the property. She seeks refuge with Darla, who reveals herself to be in league with the killers when W. E. shows up and beats her with an electric cattle prod. The two put Jenny in Darla's trunk and she leaves to pick up some pizzas for dinner.
After being tormented by Vilmer, Jenny momentarily escapes the house, attempting to drive off in Darla's car. She is stopped by Vilmer, who knocks her unconscious. She soon awakens at the dinner table, surrounded by the family, who reveal they are employed by a secret society to terrorize people that may cross their path. A sophisticated man named Rothman arrives unexpectedly, reprimanding Vilmer for his methods, before revealing an array of bizarre scarifications and piercings on his torso and licking Jenny’s face. After Rothman leaves, Vilmer flies into a rage, slashing himself with a razor and killing Heather by crushing her skull under his cybernetic leg, before knocking W. E. unconscious with a hammer.
Vilmer and Leatherface prepare to kill Jenny, who breaks free and, using a remote control to manipulate Vilmer's leg, escapes. Jenny reaches a dirt road, where she is rescued by an elderly couple in an RV. However, Leatherface and Vilmer run them off the road, resulting in the RV falling on its side. Jenny emerges from the vehicle unscathed and continues running, with Leatherface and Vilmer in hot pursuit. A cropduster appears and swoops down on Vilmer, killing him when one of the wheels grazes his skull. Leatherface screams in anguish, while Jenny looks on. A limousine pulls up and Jenny jumps in the backseat, where she is met by Rothman, who apologizes, explaining her experience was supposed to be spiritual and Vilmer had to be stopped. He offers to take her to safety before dropping her off at a hospital, where she speaks to an officer. A blonde woman, being pushed by on a gurney, meets Jenny's gaze. Back on the dirt road, Leatherface continues to flail his chainsaw in despair.
