Adélaïde is a sexually repressed woman who lives with her sister Agnès and her sister's doctor husband Michel in a large house in the middle of the snowy nowhere of Europe. Observing the affection and overhearing the sounds of lovemaking between the couple soon begin to shatter the mind of hers, and she begins to have sexual fantasies involving the husband, then fantasies about three-way relations between her, her sister and the husband, until finally progressing to extremely violent, over-the-top fantasies involving sexual torture of both her sister and other women. The affection for her sister becomes overpowering, and the film heads toward a very depressing ending.