Young Michel (Jean Marais) is in love with the attractive Madeleine (Josette Day), so he decides to tell his parents of his intention to marry her. He thinks his announcement is innocent enough; his engagement, however, threatens to reveal dark secrets lurking within his family's home. Yvonne (Yvonne de Bray), Michel's overbearing mother, concocts an elaborate scheme to drive Madeleine away, thus keeping uncomfortable household truths from being exposed.