In 1898, popular American singer Sally Sanders performs in London and attracts the attention of Leonard St. John, a pampered English heir. After a brief courtship, in which Sally establishes herself as chaste and serious, the couple marry and set up housekeeping in a modest flat. When Leonard's ambitious father Aubrey discovers that his only son has married a former chorine, he denounces Sally and terminates Leonard's allowance. With his last £50, Leonard takes Sally to Monte Carlo to gamble, but soon loses all. After Leonard confesses that he is broke, Sally is unable to tell him about her impending motherhood, but gives him her own modest savings to return to England to plead his case to his father. While Sally waits for him in Monte Carlo, Leonard, who is not trained for any activity except being a "gentleman," tries to convince his father to renew his financial support. Aubrey, however, still refuses to accept Leonard's marriage and tells his son that, if he wants money to send to Sally, he must write her a letter declaring his desire for divorce. Thus trapped, Leonard writes the farewell letter, but is so overcome with shame that he shoots and kills himself. Soon after his son's death, Aubrey discovers a letter written by Sally to Leonard in which Sally reveals her pregnancy. During the next year, Aubrey has a private detective watch Sally, who is living in Paris with her son, Leonard, Jr., and report any questionable activities. When Aubrey hears that Sally has taken a singing job in a brothel, he and his lawyer rush to Paris to declare her an unfit mother and claim Leonard, Jr. In spite of Sally's motherly pleas, Aubrey refuses to allow her even to visit her son, and without money or position, Sally has no legal recourse to fight him. Twenty years later, as World War I nears its end, the now-grown Leonard is a soldier stationed in France. An irresponsible, drunken cad who believes that all women are dishonest, Leonard seduces Eloise Duval, a young country woman, into sneaking away from her parents' home and accompanying him to an inn twenty miles away. Unknown to him, the proprietress of the inn, who calls herself Madame Blanche, is his mother. When Sally refuses to rent him a room for the night, Leonard becomes abusive to Eloise and is knocked unconscious by the bartender. After Eloise reveals Leonard's identity to her, Sally brings him to her bedroom and tends to him with maternal tenderness. Before a revived Leonard leaves the inn, still oblivious to his mother's presence, Eloise's father storms in and confronts Leonard. During the ensuing fight, Leonard shoots and kills Duval, but Sally helps him to escape before the police arrive and subsequently confesses to the deed. At her trial, Sally maintains that she killed Duval in self-defense, while Leonard follows his grandfather's advise and lies on the witness stand. However, after Leonard is re-questioned rigorously by the prosecutor, Sally is revealed to be Leonard's mother, and Leonard, the real killer. Defying Aubrey, Leonard tearfully reunites with his mother in the courtroom and later pledges to go with her to America upon his release from prison.