A banker hires a seedy detective to find his daughter and keep her safe from kidnappers.

In the 1860's, Giorgio (Giraudeau), a young Italian soldier is sent to a remote post, far away from his lover, Clara (Antonelli). He is lodged in the house of the colonel (Girotti). He becames friends with the colonel and the local doctor (Trintignant). Among the inhabitants of the house, there is a strange young woman - Fosca (d'Obici) who is both unattractive and mad. However, she has a passion that Giorgio will have to cope with.