1973, the film starts with a mention that someone's robbing graves and creating macabre monuments. From there we meet a group of young folk traveling through Texas in a van. They plan to visit the decrepit home once inhabited by the grandparents of Sally Hardesty (Marilyn Burns) and her wheelchair-bound brother Franklin (Paul A. Partain). Along for the ride are Sally's boyfriend Jerry (Allen Danziger) plus another couple, Kirk (William Vail) and Pam (Teri McGinn). On this very hot day, they see a hitchhiker (Edwin Neal) and take pity on him due to the intense heat. They quickly regret this decision, as the hitchhiker turns out to be a twitchy weirdo who gleefully cuts his own hand and also slices Franklin with a razor. He gets the boot from the van, which sets him off even more. The kids then stop to get gas but find out there's none to be had. They head out to the old house anyway and explore it. Soon they hear a generator from an adjacent home, so Kirk and Pam go to see if they can score some fuel from the inhabitants. This ends poorly for them, and this starts an experience of terror due to the psycho, chainsaw-wielding Leatherface (Gunnar Hansen).

Leatherface is the main villain of The Texas Chain Saw Massacre movies. He is a six foot four inch tall maniac who wields a chainsaw. The character was originally played by Gunnar Hansen. His real name is unknown, but fanon has unofficially suggested Robert Sawyer. His older brother Chop Top calls him "Bubba".

Leatherface is never seen without one of his human-flesh masks on, the reason being either disfigurement or psychological issues. He differs from other movie killers in that he is not so much sadistic or evi; he is severely retarded and only doing what his brothers tell him to do. The people he kills are later made into barbecue and chili, which are sold by his much older brother, Drayton Sawyer (played by Jim Siedow), whose name in the first Texas Chain Saw Massacre film was "Old Man" and "Cook". Aside from Leatherface and Drayton, the Sawyer clan includes his two brothers, Nubbin and Chop Top (real names Edward and William), as well as Grandpa and Grandma (real names unknown).

In the re-make of The Texas Chainsaw Massacre movie , Leatherface's real name is Thomas Hewitt, who suffers from a facial disfigurement. He supposedly escaped after police discovered his ranch house and found the remains of 33 people. The producers are planning on doing a prequel that will explore Leatherface's origins.