| Director | Christopher Landon |
|---|---|
| Budget | $6 million |
| Box office | $18.1 million |
Four teenagers discuss an urban legend of a serial killer known as the Blissfield Butcher. The Butcher breaks into the mansion they are in and slaughters the group before departing with an ancient dagger known as La Dola.
The next day, bullied high school student Millie Kessler attends the Blissfield Valley High School homecoming football game, where she performs as the school mascot. As she waits for a ride home near the now-empty school, the Butcher arrives and stabs her in the shoulder with La Dola, causing an identical wound to appear on his shoulder. Millie's older sister Char, a police officer, arrives and scares off the Butcher. The police collect La Dola as evidence and initiate a manhunt for the Butcher.
The following morning, the Butcher and Millie discover that they have switched bodies, and both make their way to Blissfield Valley High School. At school, the Butcher, now posing as Millie, kills Millie's chief tormentor Ryler by locking her in a cryotherapy tank in the girl's locker room. He realizes that his innocent appearance grants him immunity from suspicion and fatally bisects woodshop teacher Mr. Bernardi, another of Millie's tormentors, with a table saw. Millie, now in the Butcher's body, finds her best friends Nyla and Josh and proves her identity to them. Nyla and Josh research La Dola and discover that Millie must stab the Butcher with the dagger by midnight or the body switch will be permanent.
Later that afternoon, with the school's official homecoming cancelled, the Butcher suggests that a new dance be held at an old mill that is actually his hiding place. He lures Millie's crush Booker into a monster mini golf course to kill him, but Millie, Nyla, and Josh arrive just in time to save him. Millie knocks both the Butcher and Booker unconscious, and she and her friends bring the two to Josh's house. After tying the Butcher to a chair, Millie and Nyla try to explain the situation to Booker, who remains unconvinced until Millie recites a love poem she anonymously wrote to him weeks earlier. Josh watches over the Butcher while Millie, Nyla, and Booker drive to the police station to obtain La Dola. Nyla tricks Char, the last officer in the station, into leaving so she can steal the dagger. Waiting outside in the car, Booker reveals that he has always liked Millie, and Millie divulges how she enjoys the newfound strength and confidence she feels while in the Butcher's body, and they kiss.
The Butcher escapes Josh's house, and Char catches Nyla stealing La Dola. Still in the car, Millie sees the Butcher enter the police station and runs in after him, but Char tries to detain her, unaware of the situation. Millie overpowers Char and locks her in a jail cell while the Butcher escapes in a police car. At the homecoming dance at the Butcher's mill, the Butcher kills three jocks who attempt to rape him, thinking he is Millie, as well as a fourth who attempted to assault Josh. As midnight approaches, Millie finds the Butcher, and Nyla and Josh hold him down while Booker staves off the police. Millie stabs the Butcher with La Dole, and they switch back to their own bodies just before the police shoot down the Butcher. Millie and Booker reunite and kiss again.
After faking his death in an ambulance, the Butcher follows Millie home and attacks her, mocking her physical weakness and anxiety. Millie, Char, and their mother struggle to overpower the Butcher before Millie kills him by impaling him with a broken table leg.