Plot

A rehabilitation hospital in the Italian countryside which offers treatment for women suffering from various psychological disorders is stalked by a mysterious cloaked killer.

In a psychiatric clinic for rich women, dies murdered, one after another, a nurse and two patients, while an arrow hit another woman. The guilty is a masked man. The police decide to set up a trap, but the line of murdering isn't still over.—1felco

On a dark evening, a person wearing a hood and dark cloak approaches a large rural villa which has been converted into an asylum. The person admires some antique weapons on a wall, selects an axe and heads upstairs. In one room, an apparently agitated Cheryl is tossing and turning in her bed. She presses the buzzer for the attendants, the lights come on and the person runs away.

The next morning, Ruth is being driven to the clinic. Ruth's husband, who is driving, her tells her to think of her stay there as a vacation and that she can be back with the children. Ruth in an apparent suicide attempt, grabs the wheel and tries to run them off the road.

At the clinic, as a few attendants an patients play croquet in the front yard, Helen, a nurse, talks to resident Mara and tells her that she seems to be improving, She says she is there to help Mara, like a friend.

Ruth is dropped off as a man leads her into the building. She tries to whack him with a heavy stick but is stopped.

Meanwhile, Dr. Francis Clay asks Dr. Austin about the possibility of Cheryl being cured. Outside, Anne tries to follow the gardener, who is walking away from the clinic, but she is called back by Austin, who talks to her of her "impulsive" and "excessive" sexual desires.

Mr. Hume, Cheryl's husband, talks of a company needing Cheryl back and of her return in one week. Francis says that Cheryl's suicidal urges may relapse, but Hume thinks that his wife only needs some rest.

Meanwhile, Anne talks to Peter; he has been told by the doctors that she is getting better. Anne says that no one can calm her "passions" like Peter, but Peter is evidently not as sexually interested in the way that Anne seems to remember.

Later that evening, as the attendants and patents sit in a room to mingle and play cards and board games, Anne sneaks out the front door and runs to the greenhouse. The hooded and cloaked person is outside, and after nurse walks by (seeing and ignoring the person), she is beheaded with a scythe.

Anne sees the gardener, takes off all her clothes, approaches him and seduces him into having sex with her. Meanwhile, Helen goes to Mara's room and tells her that she can join the others if she wants and says that she will check on her later. Dr. Austin is told that Anne is missing, and the attendants go to find her.

Cheryl asks Francis if, when outside, she will be like she was before, and the doctor tells her that she has been cured. Cheryl asks to see Francis afterwards.

After having sex with Anne, the gardener tells her that she must leave for he will suffer the consequences of their tryst. Anne does not want to leave, so the gardener smack her. Anne hits him back, calmly puts her clothes back on and leaves. She walks over and kisses the male attendants that find her until Austin calls her to stop.

The killer goes back inside the clinic, gets a knife, and unlocks Ruth's door as she sleeps. The knife is places in her hand, as the killer takes off his hood and Ruth awakens. She goes for the killer with the knife, but gets knocked aside and her hands are taken and put around the killer's throat (with his face still unseen). The killer then chokes her and stabs Ruth in the chest.

Dr. Austin looks around the hallway with a flashlight and finds Helen, who says that she heard a noise. A chauffeur enters the building and drinks all of the drinks leftover from the get-together. After looking around, the killer shows up and pushes the chauffeur into an iron-maiden-esque device, and his blood pours out.

The killer walks around with a sword and angrily hits on the bed in Cheryl's empty room. Cheryl meets with Francis in the hallway and they leave together.

Mara listens to a radio and takes a bath. Helen enters the room, strips to her underwear, and helps wash Mara for a while.

Francis and Cheryl talk of their potential relationship, and he leaves to "do the rounds".

The killer walks into Anne's room, shuts her window, and takes off his hood. Anne's eyes open, she sees the killer standing over her bed and asks him to lie down next to her. The killer chooses instead to axe her to a bloody death.

In Mara's room, she dances a bit for Helen to a song on the radio. As Mara looks out of her window, the killer fires a crossbow at hits Marta in the neck with an arrow, killing her instantly. Helen screams and a crowd gathers outside her door. Austin and Francis see the dead female and Austin tells an attendant not to let anyone in the room. The two doctors and Cheryl look around the building when they find blood on the antique weapons and discover the body of the chauffeur. Francis points out that the other sword from the display is missing and Austin finally calls the police, stating to the police commissioner that the killer is still inside the clinic.

The police arrive and remove the bodies of Anne, Ruth, Mara and the other nurse from the area, but they are angry that Dr. Austin moved some weapons and tried to keep the killings a secret (essentially "helping" the killer) thus making him an accessory after the fact. The police inspector suggests using Cheryl as bait, and Francis tries to get her to rethink the idea after she agrees to it.

While all of the other clinic patents are moved into a single room for their own protection, Cheryl awaits in her room. The killer approaches with a rope to strangle where he removes his hood... finally revealing himself to be her husband Hume. The cops show up before he can finish strangling Cheryl and chase Hume around the building.

Francis and Austin theorize that Cheryl's husband wanted to kill his wife for some time and he created the idea of a maniac spree killer to that no one would suspect him of Cheryl's murder. Hume knocks out two of the cops chasing him and upon running into a room to hide, discovers all of the women patents in it. Hume goes on a brutal killing spree, killing every single woman in the room before the police run into the room and finally shoot Hume dead.