For richer, for poorer. In sickness and in health. Till disagreement does us part. Young couple Judy and Nicholas think they've stumbled upon the ideal marital formula with their 'perfect understanding'. They agree to never disagree, to maintain total independence and to 'never be husband and wife, but lover and mistress'. The pair's blissful union soon stumbles when Nicholas (Sir Laurence Olivier) admits to having an affair. Guilt stricken, he confesses his folly and a broken Judy is forced by the terms of their agreement to forgive him. Stung by his betrayal, the opportunity to get even soon becomes apparent when the confidant Ivan offers to help her settle the score in the bedroom. Will Judy and Nicholas ever rediscover the love that first brought them together?