After School Massacre

Two high school students, Devon and Jess, develop crushes on their teacher Ty Anderson and convince him to accept their Facebook friend requests. The online connection marks the first step in their plan. They imagine a closer relationship with him as the school year unfolds.

Devon and Jess accuse Ty of making sexual comments to them on Facebook and report him to Principal Wheatley. The school administrator investigates the allegation, threatening the teacher's job and reputation. The situation sets the stage for a dramatic escalation.

Wheatley fires Ty Anderson after receiving the report. In response, Anderson snaps and kills Wheatley and his secretary Linda in a furious act. The campus quiet is shattered as violence erupts at the school.

After the firing, Anderson overhears that the girls are planning to attend a slumber party. He takes this as his chance to get revenge on those who set him up. He heads to the party location with intent to strike.

Devon meets Jess and her sister Dee Dee at the party, joining their friends Erin, Alex, Steph, and Laura. Two nerds, Max and Joel, arrive to spy on the girls. The party is underway as the group sizes up their night ahead.

Dee Dee clashes with her boyfriend Luke and goes to buy more beer. While she’s away, Anderson ambushes her with a mailbox, killing her. He also kills another girl, Shelly, during the chaos. The party's mood shifts from festive to terrifying in moments.

Luke tries to force himself on Erin in Jess's bedroom. The attempted assault exposes the danger in the house and heightens the tension among the remaining partygoers. The group rallies to confront the killer instead of letting it happen.

Jess and her friends chase Max and Joel away after they were spying on the girls. The group then turns to lighthearted party games, trying to maintain a sense of normalcy amid the escalating danger. Behind the facade, the killer's presence remains unseen.

Anderson strikes again, strangling a pizza delivery boy who arrives during the party. He hides the body in a trash barrel, signaling a chilling method and a growing body count. The house becomes a scene of calculated horror.

When Max and Joel return, Joel passes out drunk in the garage while Anderson stabs Max in the throat with shears. The violence escalates sharply as the killer eliminates another witness to his crimes. The survivors realize they are truly not safe.

Laura discovers Alex's body stuffed up the chimney, demonstrating the killer's reach inside the house. Anderson then cuts Laura's throat with an electric knife, further escalating the carnage as the night wears on.

Anderson reveals that he is the killer to Jess and knocks her out. He then kills Devon by shoving a curling iron down her throat, marking another brutal act of vengeance in the party's chaos. The killer asserts dominance as the survivors scramble.

Luke discovers what Anderson has done and attacks him, but is stabbed to death with a poker. The killer leaves his mask in Luke's lifeless hand and flees the scene, signaling the end of the living witnesses' immediate danger.

The police arrive and incorrectly assume Luke was the killer. Jess crawls outside and tries to flag down a passing car, but is run over, though she survives. The night ends with the killer on the loose and the survivors traumatized by what happened.