In 1979, aspiring pornographic actress Maxine Minx embarks on a road trip through Texas with her producer boyfriend Wayne, fellow actors Bobby-Lynne and Jackson Hole, director RJ, and RJ's girlfriend, Lorraine, to shoot an adult film for the booming theatrical pornography market. Bobby-Lynne and Jackson strike up a romance, while Lorraine is unimpressed with the film's content, and RJ attempts to make it seem like a serious cinematic piece.

The group arrives at the farm of Howard and Pearl, an elderly couple in whose guest house the group intends to shoot the film The Farmer's Daughters. Howard is temperamental towards the group, brandishing a shotgun while Pearl silently stalks Maxine. As filming commences without Howard's knowledge, Maxine is invited inside the couple's home by Pearl, where they have a conversation. Pearl laments her age, expresses jealousy for Maxine's youth, and makes a sexual advance towards her. She later watches Maxine have sex with Jackson and is aroused. Pearl pleads with Howard to have sex with her, but he refuses, claiming his heart is too weak.

Night falls, and the film crew relaxes in the guesthouse. Lorraine, keen to shed her reputation as a prude and intrigued by the film, asks to participate in the shoot. RJ is immediately opposed to the idea and accuses the group of putting her up to it, though they assure him that they did not and that Lorraine’s choice to be in the movie falls on her alone, regardless of his feelings. RJ then films the scene of Lorraine and Jackson having sex. Frustrated with the change in the script and in shock by Lorraine’s unfaithfulness, RJ sets out to leave the crew stranded at the farm while they are asleep, but he is stopped by Pearl, who attempts to seduce him. When he rebuffs her, she stabs him to death. Lorraine and Wayne notice RJ is missing and go searching. Pearl kills Wayne with a pitchfork in the barn, while Lorraine is invited into the couple's house by Howard, who claims Pearl is missing and asks Lorraine to retrieve a flashlight from the basement. When Lorraine attempts to leave the basement, she discovers she has been locked in. After turning on the light, she discovers the rigged corpse of a male sex slave.

Howard approaches the guest house and asks Jackson to help him locate Pearl. Jackson finds a submerged car in a pond (belonging to the corpse in the basement) before Howard shoots him dead, revealing himself to be complicit in Pearl's violent tendencies. Meanwhile, Pearl enters the guest house and climbs into Maxine's bed naked. Maxine awakens and screams, causing Pearl to flee the house, which Bobby-Lynne witnesses. In the farmhouse, Lorraine uses a hatchet to break through a panel in the basement door, but Howard attacks her, breaking her finger, and forces her back inside. Bobby-Lynne follows Pearl outside to the nearby lake and tries to guide her away from the water. Pearl angrily accuses Bobby-Lynne of being a whore before pushing her into the lake, where she is devoured by an alligator.