Backwoods is a slasher horror film and the first in the popular Backwoods franchise. However, it is sometimes seen as a clone of the Friday the 13th series.
The film begins with a biker gang pinning down a young woman by the roadside and gang raping her. Several years later, a group of friends arrive at the same forest to take a hike, led by local guide Earl. The group consists of Tim, Mikey, Dave, Sean, Penny, Sam and Jess. The group depart into the woods, led by Earl.
During the trip, the group stops by a river to splash around. Jess and Sean begin to have sex, when suddenly Mikey pops out wearing a mask. Sean gets angry and he and Jess get into an argument with Mikey. An upset Mikey storms off after the rest of the group get involved, but not before stealing their map. After he leaves, the group decide not to worry until Earl admits that he could only navigate the area using the map or a certain path, which has been washed away by unusually heavy rain. They hear Mikey screaming for help but agree that he is just pranking them again.
Earl tries to find a way to a peak to get a good view, but as he climbs up, an unseen assailant cuts the rope and he falls, breaking his leg. The group confront Earl and he explains the local legend; the young woman who was raped in the opening bore a child as a result of the gang rape, but it was severely disfigured and poorly at birth. In spite of the nature of its conception, she loved the child unconditionally; even if her highly religious family did not. The baby died shortly thereafter and the woman vanished into the woods. Rumour has it that she does not take kindly to strangers in her woods. The gang split up to look for a possible route home, with Sean staying with the injured Earl. Sean then goes to urinate, allowing an unseen person to crush Earl's head with a huge rock. When Sean returns, he finds the body and is struck over the head with a hatchet.
Meanwhile, Dave tries to seduce Sam but they get into a fight and he walks straight into a mantrap. As she goes to get help, he is struck through the head with the hatchet. Realising that someone is knocking them off, the remaining group decides to stick together.
They eventually happen upon a decrepit cabin with a terrible stench. With the sun going down, Penny and Jess go to bathe in a nearby river, and Tim gives them a hunting knife for defense. While they are gone, he sleeps with Sam. Afterwards, Sam descends into the cellar and screams as she finds Mikey's decapitated head and the rotten corpse of an old woman. Upstairs Tim is attacked and knocked out. The killer then descends into the cellar and murders Sam by stabbing her through the face with large machete.
Jess and Penny return to find both of them missing. As they search the house, Penny goes into the cellar and begins screaming when she happens upon the bodies. The killer locks her in and then goes upstairs, where he corners Jess. Although she pleads for her life, the killer strangles her to death a piece of barbed wire.
The killer returns to the cellar as Tim wakes up. He explains that he thinks he has figured out what is going on; the decayed corpse is that of the woman who was raped and impregnated, and the killer is her deformed son. As the killer arrives in the cellar, he ties Tim up and shows Penny a locket containing a photo of his mother when she was younger, and she sees that she resembles herself. Suddenly, she stabs him with the hunting knife Tim gave her earlier. As she unties him, the killer attacks them. As he wrestles with Tim, Penny grabs an old sweater belonging to his mother. The killer stops and looks at her briefly, allowing Tim to retrieve the knife and stab the killer multiple times in the chest. The film ends with Tim and Penny limping away together.