In Baltimore, Maryland, on Dec 20, 1918, Elizabeth MacDonald receives word that her husband of one year, John Andrew, has been killed in war-torn France. Devastated by the news, Elizabeth faints on the job at the Hamilton Chemical Works, and is taken in by Larry Hamilton, her caring boss. Larry's maiden aunt Jessie soon informs him that the grief-stricken Elizabeth is pregnant. In a German hospital, meanwhile, the heavily bandaged John is tended to by the understanding Dr. Ludwig. Despite Ludwig's attempts to discover his identity, a depressed, morose John refuses to give his name and is determined to remain an official casualty of the war. Back in Baltimore, Elizabeth gives birth to John Andrew, whom she nicknames "Drew," and accepts the proposal of the devoted Larry. Many years later, as the threat of war in Europe again looms large, Elizabeth adopts an isolationist stand, hopeful that Drew, who is now twenty, will not be called to duty. At the same time, the crippled, scarred John, who lives in Austria and calls himself Erich Kessler, prepares to return to Baltimore with his foster daughter Margaret and work as a chemist at the Hamilton factory. Upon arriving in Baltimore, John takes Margaret to the house in which he and Elizabeth once lived and inquires about its owners. John then reports to his new employer, Larry, and unaware of his connection to Elizabeth, accepts his dinner invitation. John is stunned when he sees Elizabeth for the first time, and while Elizabeth is unable to identify John's surgically altered face, she senses something familiar about him. An anxious John then is introduced to Drew and deduces that he is his son. To Elizabeth's horror, Drew announces after dinner that he wants to join the RAF, which is training in Canada. Later, after Elizabeth has told Drew she will not permit him to enlist, Drew discusses the Nazi situation with John, who has come to the Hamiltons' for lunch and is sympathetic to his son's position. When Drew brings the subject up again at the table, Elizabeth explodes with anger and tells Larry, who supports Drew, that because Drew is not his real son, he cannot know the pain she is feeling. Elizabeth then tells John that he is not welcome at her house anymore, but later apologizes when he reveals that Margaret's real parents, Dr. Ludwig and his wife, were brutally murdered by the Nazis. After John leaves, Elizabeth finds herself reminiscing about her first marriage. Then, on the twenty-first anniversary of that marriage, both Elizabeth and John are drawn back to their old house, and Elizabeth finally confronts John about his identity. Although John repeatedly denies her assertions that he is her long-lost husband, Elizabeth later calls him at work when she discovers that Drew has disappeared. Concerned, John reads a letter that Drew had left for the absent Larry and rushes to the train station to intercept his son. John tells an indignant Drew that he has to wait until he is twenty-one to enlist and threatens to inform the police if he resists. After an exhausted John returns Drew safely home, Elizabeth once again presses him to admit his identity. Instead, John tells Elizabeth that she must stop living in the past and face her fears. Moved by John's thoughtful remarks, Elizabeth gives Drew permission to enlist and explains to him that John interfered so that she could send him off herself. John, meanwhile, collapses at home while burning a cherished love letter from Elizabeth and then dies. The next day, Elizabeth and Larry go to John's place to tell him about Drew and are saddened to learn of his death. When a tearful Margaret tells Elizabeth that John had assured her that she would be there if anything happened to him, Elizabeth embraces the child, confident that "tomorrow is forever."