The Truth About Youth - William A. Seiter

Richard Carewe has raised his deceased friend's son from childhood with the help of his housekeeper and her beautiful daughter, Phyllis. He arranges a marriage between Phyllis and the boy, but the rascal impulsively marries a notorious nightclub singer, "the Firefly", instead. The femme fatale dumps the boy when she discovers he has no money, but by then Phyllis realizes she is in love with Richard, not his foolish ward.