Set in nineteenth-century France, a young man Jean Berlot is plagued by nightmares in which he is taken to a madhouse. On the journey back from his mother's funeral, he is invited by a Marquis to spend the night in his castle. There Berlot witnesses a blasphemous orgy and a 'therapeutic' funeral. The Marquis helps him conquer his fears and takes his guest to an asylum where the patients have complete freedom and the staff are locked up behind bars.