High school students Kelly, Jasmine Waltz and Gary Jardine, Charles Solomon Jr., are camping out at night when an unseen assailant stabs Gary to death and impales Kelly with a hiking stick. The next day, the Bridgemont High cheerleading squad—Parker, Angela, Tammy, Shelley, and Dina—practices before heading to an event in another town. In the locker room, Shelley mourns their former teammate, Marissa, who died exactly one year ago. As the group is leaving, Dina goes back inside to grab her purse and is killed. They assume she took the bus and depart in a van with their coach, Ms. Hendricks, their driver, Buzzy, and students Mark and Ryan.
Bobcat County Sheriff Frank Murdock and Deputy Donna Adams are alerted by the Fresno Police chief that Jeremiah MacPherson, a serial killer who escaped from a mental hospital the day before, is believed to be moving toward their area. Meanwhile, a jogger named Debbie is killed when someone cuts the ropes of the suspension bridge she crosses. Murdock, Adams, and Officers Kimble and Phillips investigate Kelly and Gary’s murder. They visit retired Sheriff Monty Coltrain, who arrested MacPherson 20 years ago, to warn him of the escape. While there, they learn that Dina has been found gutted at the high school, which doesn’t fit MacPherson’s usual MO. When Phillips and Kimble stop to examine a jacket left by the roadside, MacPherson ambushes and kills them both and steals their squad car. Murdock and Adams then visit one of MacPherson’s surviving victims, Linda, hoping her recollection will yield clues; a flashback reveals his brutal attack in the high school with a large power drill, leaving her for dead.
The cheerleaders encounter a roadblock and are told they must detour, so Buzzy drives them through a snowy mountain pass. The van runs out of gas as the storm worsens, and the group seeks refuge in an empty vacation cabin. The Fresno Police chief’s assistant, Melissa DeMarco, calls Sheriff Murdock to inform him that MacPherson used Debbie’s cell phone to call their station and left a voicemail implying he is not acting alone. Deputy Adams learns that the cheerleaders have gone missing, and she and Murdock set off to search.
MacPherson arrives at Monty’s cabin in the stolen squad car. The two exchange gunfire, and MacPherson flees into the woods. Buzzy goes outside to investigate the gunshots but is distracted when he spots Tammy and Ryan having sex through a bedroom window. The killer sneaks up and kills him with an axe. Mark goes outside to look for Buzzy and is decapitated. The others discover his body and search for a gun. Ryan finds one, and he and Angela go for help. They become separated, and Ryan is strangled. Ms. Hendricks, Parker, Shelley, and Tammy go outside to look for the fuse box. Shelley finds it and is electrocuted when she touches it. Tammy is pulled into the crawlspace and stabbed repeatedly. Monty finds Shelley’s body while tracking MacPherson, and Ms. Hendricks and Parker ambush him, knock him unconscious, believing he is the killer. Angela later confronts them at gunpoint, revealing that she killed the cheer squad to avenge Marissa’s death. The others manage to elude her, and Parker confesses to Ms. Hendricks that the girls had slipped ecstasy into Marissa’s drink at a party and filmed her making out with Angela. They used the video to blackmail Angela into going along with it.
Ms. Hendricks and Parker turn on the gas stove and throw a Molotov cocktail into the cabin as Angela reenters, causing it to explode and killing her. The next morning, Deputy Adams talks to them in front of Monty’s house as Sheriff Murdock sends Monty off in an ambulance. As the vehicle pulls away, the driver is revealed to be MacPherson.
