After World War I, Frenchman Paul Renard is haunted by the memory of Walter Holderlin, a German soldier he killed in the heat of battle. Having read and signed Walter's last letter and memorized his home address, Paul goes to Germany to confess his deed to the soldier's family. Anti-French sentiment is strong in Germany and Dr. Holderlin will not suffer Paul's presence in his home until Walter's fiancée Elsa recognizes Paul as the man who has been leaving flowers on Walter's grave. Paul reveals that he knew Walter, but is unable to confess his past, and tells the grateful family he and Walter were friends during the war. Paul and Elsa fall in love and a close bond grows between Paul and the Holderlins, despite the entire town's disapproval. When Elsa shows Paul Walter's former bedroom, he is unable to contain himself any longer and confesses the truth to her. Paul also reveals his plans to tell Dr. and Mrs. Holderlin his secret and then leave, but Elsa intervenes and advises him that his confession and departure would deprive the Holderlins of their second "son." Eventually, Elsa convinces Paul to sacrifice his conscience and stay to make the Holderlins happy. After Paul consents, Dr. Holderlin gives him Walter's violin to play to Elsa's accompaniment.