Intruder

The supermarket closes for the night and Craig, Jennifer's ex, returns to quarrel with her. Linda presses her security button, and Bill, the co-owner, arrives to break up the fight. A brawl erupts and Craig escapes onto the shop floor as Jennifer calls the police.

Owners announce the store will be sold, and the night crew is put to work marking down stock before closing. Craig makes telephone calls to the store, upsetting Jennifer. The police arrive but tell everyone to be careful.

Police arrive but offer no real help, simply telling the group to be careful. The tension remains high as the staff braces for the night ahead.

After finishing her shift, Linda is stabbed by an unseen assailant, plunging the store into chaos. Bill spots someone trying to enter through the back door and goes outside to investigate, where he finds Craig watching Jennifer through the bathroom window and is rendered unconscious.

Back inside, the killer begins to brutally murder the employees and scatters their severed body parts around the store. Jennifer investigates and discovers several bodies and body parts in the storerooms. Terrified, she is attacked by the killer but manages to escape back to the shop floor.

Hearing someone at the door, she tries to draw their attention, but the person has left by the time she gets there. Craig grabs her, but she beats him with a meat hook.

Bill staggers in, claiming that Craig attacked him outside, and proceeds to call the police. Jennifer notices Bill's hands are stained with blood and begins to suspect that he is the killer behind the murders.

Bill explains that he couldn't let his partner sell the store, so he killed him and got carried away, killing everyone. He attacks Jennifer and chases her around the locked building. A delivery man appears outside, but Bill kills him before Jennifer can draw attention.

Craig tells Jennifer he saw Bill killing Linda, and that he climbed into the building through the bathroom window to save her. Bill appears and bludgeons Craig while Jennifer flees.

Crawling out the bathroom window, Jennifer tries to escape in her car but finds Linda's body inside. Bill grabs her legs and pulls Jennifer under the car, but she stabs him with a knife.

She heads to a phone booth to call the police, but Bill reappears and starts to smash the booth to get at her. He topples the phone booth over and traps her, but Craig appears and brutally damages him with a meat cleaver.

When the police arrive, one of the officers finds the carnage in the store. The severely injured Bill claims that Jennifer and Craig are responsible for the attack, but the policemen ignore his protests and arrest them.

Bill suddenly opens his eyes as Jennifer screams, leaving the outcome of their fate unknown. The frame lingers on the carnage and the police taking away the suspects, suggesting the terror may not be over.