Heartless Husbands (1925)

Sonny Cain, an orphan, is adopted by James Carleton, an ex-convict who sees to it that Sonny treads the straight and narrow path. Carleton is later sent to jail again and is not released until Sonny attains manhood. Sonny falls in love with Mary Kayne and asks permission to marry her, but Mary's father reveals that he himself is Sonny's father. Carleton doubts the story and rifles Kayne's safe to find proof that Kayne is lying. Carleton is surprised by a detective, who shoots him; the wounded Carleton then tells the detective that Kayne is a thief. Kayne is arrested and given truth serum to make him talk. Kayne confesses that he is not indeed Sonny's father, and the lovers are free to marry.