Suspiria :

Suzy Bannion, a young American ballet student, arrives in Freiburg, West Germany, to study at the co-ed Tanz Akademie, a prestigious dance school. She sees another student, Pat Hingle, flee the school in terror. Suzy is refused entry to the school and forced to stay in town overnight. Pat takes refuge at a friend's apartment and tells her that something sinister happened at the school. Pat is ambushed by a shadowy figure who stabs her repeatedly before hanging her with a noose by throwing her through the apartment building's skylight. Pat's friend is also killed after being impaled by a falling shard of glass while trying to alert other tenants to the murder.

Suzy returns to the school the next morning, where she meets Miss Tanner, the head instructor, and Madame Blanc, the deputy headmistress. Tanner introduces Suzy to Pavlos, one of the school's servants. She also meets classmates Sara and Olga, her new roommate. Suzy experiences an unsettling encounter with one of the school's matrons and Blanc's nephew, Albert, before passing out during a dance class. When she regains consciousness, Suzy learns that Olga has thrown her out of her apartment, forcing her to live at the school with Sara in the room next door.

One night, maggots fall from the ceilings of the students' rooms due to a shipment of spoiled food in the attic, forcing them to sleep in one of the dance studios. During the night, a woman enters the room but is obscured by a curtain hung around the room's perimeter. Sara, frightened by her hoarse and labored breathing, recognizes her as the school's headmistress, who is supposedly out of town. The next day, the school's blind pianist, Daniel, is abruptly fired by Miss Tanner when his German Shepherd bites Albert. Daniel is stalked by an unseen force while walking through a plaza that night; his dog turns on him and viciously rips out his throat.

Sara tells Suzy that she was the one on the intercom who refused her entry the night Pat was murdered. She reveals that Pat was behaving strangely before her death and promises to show Suzy the notes that she left behind. Sara finds that Pat's notes are missing and is forced to flee when an unseen assailant enters the room. They pursue her through the school before cornering her in the attic. She escapes through a small window but falls into a pit of razor wire, entangling her before her pursuer kills her by slashing her throat.

The next morning, Tanner tells Suzy that Sara has fled the school. Suspicious, Suzy contacts Sara's friend and former psychiatrist, Frank Mandel. He reveals that the school was established in 1895 by Greek émigrée Helena Markos, who was allegedly a witch. Suzy also consults with Professor Milius, a professor of the occult. He reveals that a coven of witches draws its strength and power from its leader, and without a leader, the coven will perish.

Suzy returns to the school to find that everyone has left to attend the Bolshoi Ballet. Recalling a conversation with Sara about footsteps, she follows the sound of them carefully, leading her to Madame Blanc's office. Remembering that Pat uttered the words "secret" and "iris" the night that she was killed, Suzy discovers a hidden door that opens by turning a blue iris on a mural in Blanc's office. Suzy enters the corridor and finds the academy's instructors, led by Madame Blanc, plotting her demise in the form of a human sacrifice. Albert alerts Pavlos to Suzy's presence. Suzy hides in an alcove, where she finds Sara's disfigured corpse.

Pursued by Pavlos, Suzy retreats to Helena Markos's bedroom. Suzy finds Markos sleeping, recognizing her as the headmistress by her labored breathing. She accidentally wakes her by breaking a decorative peacock. Markos renders herself invisible and taunts Suzy before reanimating Sara's mutilated corpse to murder her. When flashes of lightning inadvertently reveal Markos's silhouette, Suzy impales her through the neck with one of the peacock's broken glass quills. Markos's death causes Sara's corpse to vanish.

Suzy flees as the school academy starts to explode. Tanner, Pavlos, and the rest of the coven perish without the power of Markos to sustain them. Suzy escapes into the rainy night as the school is consumed by fire.

Profondo Russo ( Deep Red ) -

In 1956, during Christmas at a family home, an unseen figure stabs another to death. A bloody knife falls to the floor, close to a child's feet.

Twenty years later in Rome, Professor Giordani chairs a parapsychology conference featuring psychic medium Helga Ulmann. Helga is suddenly overwhelmed by the "twisted, perverted, murderous" thoughts of someone in the audience. Speaking later with Giordani, Helga says she believes she can identify this person, unaware that someone is listening from the shadows.

Later that night, a black-gloved figure invades Helga's apartment and kills her with a meat cleaver. English Jazz pianist Marcus Daly sees the murder from the window as he passes by and rushes to her apartment, finding her mutilated corpse. After the police arrive, Marcus thinks one of the apartment's paintings has disappeared, but he cannot pinpoint what exactly is missing.

The media identifies Marcus as the eyewitness and shows reporter Gianna Brezzi's photo of him. The next morning, Marcus visits the home of his heavy-drinking friend, Carlo, but only finds Carlo's eccentric mother Martha, who seems interested in Marcus. That night, the killer plays a recording of a child's song outside Marcus's door; he manages to lock the door before the person can enter, but he hears the gruff whisper, "I'll kill you sooner or later." Feeling guilty for endangering him by taking his photo, Gianna begins helping Marcus investigate.

Marcus tells Giordani, whom he met at Helga's funeral, about the encounter. Giordani, noting that Helga also mentioned hearing child's song during her vision, recalls a book of modern folklore describing a local haunted house where a child's song is sometimes heard. Marcus finds the folklore book at the library. He rips out a picture of the house and plans to learn more by visiting the book's author, Amanda Righetti. However, the killer, who has been watching Marcus, attacks Amanda and drowns her in scalding water before Marcus arrives.

Marcus uses the photo from the book to find the huge, abandoned house. Under sheetrock he uncovers a disturbing mural: a child holding a bloody knife over a dead body. After he leaves, a loose chunk of sheetrock falls away, revealing another figure in the drawing. Meanwhile, Giordani, who has been assisting Marcus's investigation, is murdered by the killer after being distracted by a large mechanized doll.

Continuing his search of the abandoned house, Marcus finds a walled-off room. In the middle of the dusty floor sits a desiccated corpse. Someone knocks Marcus unconscious as he backs away in horror. He awakens outside the house, which is burning. Gianna appears, explaining that she got his message about investigating the house and arrived in time to save him. Marcus and Gianna wait for the police in the house of the caretaker, whose daughter has drawn a picture identical to the hidden mural Marcus found in the house. She tells him she saw the picture in the archives of the local school.

Marcus and Gianna immediately go to the school and find the picture, which proves to be the childhood work of Marcus's friend Carlo. Gianna leaves to call the police and encounters Carlo, who stabs her. Pursued by Marcus and the police, Carlo runs into the dark street and is hit by a garbage truck, which snags his clothing and drags him until an oncoming car runs over his head. Gianna is hospitalized and survives the stabbing.

Marcus remembers that on the night of Helga's murder he met an utterly intoxicated Carlo coming from a different direction than the killing, meaning that Carlo couldn't have been the killer. Returning to Helga's apartment, Marcus has an epiphany: the supposed painting he saw on the night of the murder, and was subsequently unable to find, was really the killer's reflection in a mirror. As Marcus realizes he saw Martha, Carlo's mother, she appears behind him with a meat cleaver. Martha explains that after her husband said he would re-commit her to an insane asylum, she murdered him in front of the young Carlo. She walled off the room containing his body. Carlo, scarred psychologically, compulsively drew the scene as a youth and as an adult tried to repress the memory of the homicide with alcohol: he attacked Marcus and Gianna to protect his murderous mother from their investigation.

Martha attacks Marcus and wounds him with the cleaver. After Martha's necklace tangles in the bars of the building's elevator, Marcus sends the elevator down, decapitating her.