Yngsjömordet (1966)

Sweden 1889. The young Per Nilsson has a very dominant mother, Anna Månsdotter. His father died many years ago and he and his mother have for a long time been in a incestuous relationship. But Per marries Hanna for the sake of her money and Anna is mean and evil towards her, and Per refuses to have sex with her. She starts to suspect that something is going on between her husband and stepmother.