The murder of two college students (and one's boyfriend) leads to a manhunt for the killer, whose chief weapon is a red and black ascot to strangle his victims. When a young college student discovers that she recognizes the murder weapon, she becomes a target of the killer and agrees with one of her friends, who is friends with their art history teacher, to stay at a local villa located on a nearby cliff.
However, the isolated cliffside villa offers no protection from the killer, who runs over the street vendor who he buys his scarves from and who tried to blackmail him for his silence. At the same time, a young college student who is obsessed with one of the four girls and has been actively stalking her (and wearing a similar red and black scarf) and one of the locals in town, go up to the villa to spy on the girls only to be ruthlessly killed. The young student who invited her friend to the villa breaks her ankle and a doctor gives her a sedative; as such, she is asleep when the killer makes his way into the house and kills the girls, including the one who can identify him. She wakes up in time to watch him dismember the bodies but hides to avoid detection. However, the killer locks the house, trapping her inside while he prepares to dispose of the body. When he realizes that the last girl is alive, he baits her into coming out of the room she is hiding in and reveals himself to her.
The killer is the art history teacher that the final girl had befriended. He is revealed to be insane and anti-woman, stemming from a childhood incident where as a kid, a friend of his stole a young girl's doll and placed it near the edge of the cliff. He would only retrieve it if the young girl let him see her naked crotch; she reluctantly agreed but at he stood over the edge of the cliff to retrieve the doll, the young girl freaked out and screamed, causing him to lose his balance and fall to his death. This led to him to believe all women are lying whores that use men and cause them nothing but death in the process. He reveals to his female student/friend that the first two victims were students of him who seduced him into a three way and then blackmailed him with the knowledge of the affair. He then killed the rest at the villa to cover his tracks and reveals that his scarf was the opposite color scheme of the male student he killed: black on red instead of red on black. However, as he begins to kill the young woman to ensure his crime spree is never exposed, the doctor shows up and after a struggle, kills the teacher.
Who does the killer blackmail for his silence?
street vendor who he buys his scarves from