French horror directed by Pierre Chevalier and starring Howard Vernon and Brigitte Carva. The story follows Dr. Garondet (Paco Valladares) as he travels to meet the mysterious Dr. Orloff (Vernon) at his request, despite the reservations of Garondet's friends. When he arrives at Orloff's forboding castle he is confronted first by the doctor's daughter Cécile (Carva) who is concerned for her father's sanity. When Garondet meets with Dr. Orloff himself however he suggests that his daughter is the one who is deranged due to a past incident involving his experiment with an invisible being. Garondet spends the night in the castle and soon enough he is confronted with the true extent of Orloff's insanity.