Description
Suzy Bannion, a young American ballet student, arrives in Freiburg, Baden-Württemberg, Germany during a torrential downpour to study at the co-ed Tanz Dance Akademie, a prestigious German 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 and drags her to the roof of the apartment building before hanging her with a noose by throwing her through the building's skylight. Pat's friend is also killed after being impaled by falling debris 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 Sarah 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 Sarah in the room next door.
While the students are preparing for supper one night, maggots rain down from the ceilings of their 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. Sarah, frightened by her hoarse and labored breathing, recognizes her as the school's headmistress, who is supposedly out of town. 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.
Sarah 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. Sarah 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 before falling into a pit of razor wire, entangling her and allowing her pursuer to kill her by slashing her throat.
Suzy investigates Sarah's disappearance the next morning. Tanner tells her that Sarah has fled the school. Suspicious, Suzy contacts Sarah's friend and former psychiatrist, Frank Mandel. He reveals that the school was established by a 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 perishes without their leader, from whom they draw power.
When Suzy returns to the school, she finds that everyone has left to attend the Bolshoi Ballet. After being attacked by a bat and recalling a conversation with Sarah 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 Sarah'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 with crystal plumage. Markos renders herself invisible and taunts Suzy before reanimating Sarah'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 Sarah's corpse to vanish.
Suzy flees as the school starts to implode. Madame Blanc, Miss 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.
