He Knows You’re Alone

A young bride is murdered on her wedding day by the man she rejected for Len Gamble, a detective. The crime sets a grim tone and establishes the killer's ruthless pattern that will haunt the story.

Several years later on Long Island, Marie is stabbed to death inside a movie theater while her friend Ruthie sits nearby. The killer, Ray Carlton, disappears into the night, leaving the case unresolved.

The next morning Ray Carlton arrives on Staten Island and observes Amy Jensen from a distance. Amy, meanwhile, is preparing for her upcoming wedding to Phil.

Amy and her fiancé Phil, along with friends, prepare for the wedding and the associated celebrations. The looming threat from Ray adds tension to their plans.

Amy, Nancy, and Joyce attend a ballet class where they run into Carl, the philosophy professor with whom Joyce is having an affair. The encounter complicates the relationships surrounding Amy.

Amy goes to a dress fitting and notices she is being followed by an unknown man. At the ice-cream shop, she is startled by Marvin, her ex-boyfriend who works at the morgue.

Unbeknownst to Amy, Ray stabs the dressmaker to death in the dress shop as she leaves. The murder marks Ray’s increasing boldness and his reach into Amy’s life.

Nancy and Joyce throw a small bachelorette party for Amy at her home, where a power outage heightens the tension. Carl investigates and returns to find Joyce dead; Ray then kills Carl.

The following morning Marvin arrives at Amy's house, signaling a possible rekindling of their relationship. Amy reveals she has doubts about marrying Phil as fear and suspicion linger.

Amy invites Marvin to join her, Nancy, and Diane at the amusement park, but Marvin declines due to a morgue shift. They meet a student named Elliot who questions Amy about the stalker.

While riding a dark ride with her sister, Amy spots Ray inside the ride and later confides in Nancy about the stalker. The threat to Amy intensifies as the night progresses.

Nancy is killed and Amy later discovers Nancy’s severed head in the fish tank. Amy is attacked by Ray, escapes by car after a crash, and runs to the morgue for help with Marvin.

Ray pursues Amy through the morgue’s basement while Detective Len Gamble arrives to intervene. Gamble is wounded and Ray stabs him in the heart, continuing the pursuit.

Amy traps Ray in a storage closet and escapes the morgue with Marvin. Police arrive as they flee, and Marvin and Amy plan to marry, signaling that Amy has ended her engagement to Phil.

In the wedding night finale, Amy sits in her wedding dress and a mysterious intruder approaches. She confronts the figure, asking Phil what are you doing here, before screaming in horror.