This avant-garde drama follows Harry (Alan Bates), a British writer living in France who blurs the lines between reality and his own fiction. Deeply dissatisfied with his life, Harry engages in a passionate, secret extramarital affair with a beautiful woman named Natalie (Dominique Sanda). As the relationship intensifies, it becomes increasingly unclear whether the affair is genuinely happening or if it is merely an elaborate, tragic story Harry is constructing in his own mind to escape his mundane domestic reality.