Prom Night - 1980 [Kosjeyr]

In 1974, 11-year-olds Wendy Richards, Jude Cunningham, Kelly Lynch, and Nick McBride play hide and seek in an abandoned convent. 10-year-old Robin Hammond tries to join them, but they start teasing her by repeating "Kill! Kill! Kill!". Robin is backed towards a window from which she falls to her death. The children make a pact not to tell anyone what happened and keep the incident a secret, but after they leave a shadow falls across Robin's body. A rapist is mistakenly blamed for Robin's death instead and is arrested.

Six years later, Robin's family attend her memorial on the anniversary of her death. Robin's teenage sister and brother, Kim and Alex, are also preparing for the school prom to be held that evening. Their parents will also attend, as their father is the school principal. Kelly, Jude and Wendy receive threatening phone calls from an unknown figure, while Nick ignores his ringing phone. Kim and Nick, whom she is dating, are attending prom together; Jude is asked by goofy jokester Seymour "Slick" Crane who she meets by chance that morning; Kelly is going with her boyfriend Drew Shinnick (who is preoccupied with having sex with her despite her objections), while Wendy, previously Nick's girlfriend, asks the school rebel, Lou Farmer with plans to embarrass Nick and Kim at prom.

In the changing room after gym class, Kim and Kelly discover the locker room mirror severely cracked and a shard missing. The offender blamed for Robin's death has escaped and Lt. McBride, Nick's father, investigates. During the senior prom Kim and Nick perform a dance number to impress Wendy who had insisted Nick would be getting back with her after the prom. Kelly and Drew make out in the changing room, but Kelly refuses to continue to full sex. Drew angrily leaves. As Kelly gets dressed, a masked killer slits her throat with the mirror shard. Jude and Slick have sex and smoke marijuana in his van outside school grounds. However, they are being watched by Kelly's killer, who kills Jude by stabbing her throat. Slick brawls with the killer while attempting to drive away. The killer escapes from the van as it tumbles off a cliff and explodes, crushing and burning Slick to death in the flaming wreckage. McBride, staking out the prom, is informed that the sex offender blamed for Robin's death has been caught. He is relieved and ends his scrutiny of the event.

Wendy is confronted by the murderer, now using a felling axe and is chased through the school. After evading the killer several times, she is caught and hacked to death with the axe after she finds Kelly's body. Kim and Nick prepare to be crowned prom king and queen. Wendy's plan is put into action by Lou and his lackeys who tie up Nick with Lou taking his crown and assuming his position back stage. Thinking he is Nick, the assailant sneaks up behind Lou with the axe and decapitates him.

Lou's head rolls onto the dance floor, sending the partygoers fleeing in horror. Kim finds Nick and frees him. As they prepare to escape, they are confronted by the killer who attacks Nick. After Kim hits the killer in the head with his own axe, Kim and the killer stare at each other for a moment, Kim realizes who he really is. He runs outside where the police have arrived. As guns are raised Kim screams for the officers not to shoot. The killer is revealed to be Alex, who tearfully tells his sister that Jude, Kelly, Wendy and Nick were responsible for their sister's death, dying in Kim's arms as he cries Robin's name.