Christopher (Benedict Cumberbatch) is an aristocratic gentleman who believes in the traditional morality of the chivalric era. He is upright, tolerant and self-disciplined. Sylvia (Rebecca Hall) is a typical socialite. She has many lovers and lives a life of debauchery. However, an unexpected pregnancy forced her to marry the conservative Christopher in order to save her reputation. The boring life after marriage and her husband's indifference and tolerance made Sylvia crazy, and she began to use all means to stimulate Christopher. Sylvia's elopement with her old lover became the beginning of the conflict between the two, but their religious beliefs did not allow them to divorce. In this way, this barely maintained marriage plunged the two into endless torture. Christopher unexpectedly met Valentin (Adelaide Clemens), a modern woman with radical ideas and profound knowledge. Further contact made these two people from seemingly different worlds fall in love, but secular ties prevented the two from further developing this relationship. At the same time, Sylvia also realized the crisis of her marriage, began to restrain her life and work hard to save her marriage, and showed goodwill to her husband. The advent of World War I and Christopher's enlistment in the army put this love triangle relationship to the test and choice. The film is adapted from Ford Madox Ford's novel of the same name.