Denis, a poor student in philosophy, works as a night porter in the Paris market of Les Halles in order to pay for his studies. Constantly weary, he falls asleep and dreams of a beautiful girl in white, Irène, with whom he falls in love.
A religious fanatic finds his entire life and philosophy turned upside-down as he falls in love with a girl and kills her in a jealous rage. His search is for peace of mind and a desire to justify the murder of the girl to himself. His mind becomes distraught as he gropes trying to rationalize his deed and his world falls apart around him. A police inspector patiently and tirelessly stays on Barrault's trail, without putting him under arrest, though convinced he is the murderer, and waiting for the moment when he feels Barrault will break under the strain of his own religious fanaticism.
A legend about the Malveneur family tells of how their ancestor sold his soul to the devil and was cursed: man by day, wolf by night. The last of the Malveneurs is a scientist who carries out strange experiments on... nobody knows exactly what the does in the underground. The wife has a heart condition, her sister-in-law is a authoritarian lady. And nights in the old castle are not exactly peaceful.
