Karl Gunther (Klaus Kinski), the demented son of a Nazi surgeon and war criminal, runs a boarding house for young women, who are all blissfully unaware he is a voyeuristic madman.
He is a conscientious landlord who looks out for his young and attractive tenants.
Jessica (Carole Francis), the rising young soap opera star, Harriet (Barbara Whinnery), a sensuous and vivacious secretary and Sophie (Tane McClure), an accomplished pianist who enjoys wild fantasy sex with her boyfriend – they all live in Karl’s well-kept apartments.
The only discord is the “tap, tap, tap” sound at night from the crawlspace above their rooms. Karl tells them it’s rats but, in reality, it is Karl.
The sinister landlord has built a network of spaces and secret passageways between the walls so he can spy on his tenants.
One by one they become his victims, with each one put to a gruesome test while he secretly carries out horrific acts of murder and torture in hidden rooms.
Dr Karl Gunther
Kenneth Robert Shippy