Every night a howl is heard outside the insane asylum run by Professor Oder, terrifying his younger wife Silvia. Neglected by her husband she begins to fall for Adamo, a musician who is resting at the clinic to recover his health. When a patient is strangled her husband puts the blame of Adamo who he claims is a homicidal maniac. However, it turns out the professor is really insane and the night screams are his own cries of torment.