The Lone Wolf's Daughter (1919)

At a London auction, Princess Sonia bids against her husband, exiled Prince Victor, for a Corot landscape in which incriminating letters Sonia wrote are hidden, but it is bought by Michael Lanyard, who is suspected of being the mysterious, international thief "The Lone Wolf." After Lanyard gives Sonia the letters, she divorces Victor, marries Lanyard, and dies after bearing their daughter Sonia. Years later, Sonia, who thinks she is the daughter of the Princess' maid, is found by Victor, now the leader of an underworld gang of Asian crooks and Bolsheviks. Saying he is her father, Victor brings her to his home, hoping to entice Lanyard to make an appearance. When Sonia discovers the gang's plan to pump poisonous gas into Buckingham Palace and the homes of the wealthy so that Victor would be England's dictator, she tells Roger Karslake, Victor's secretary, whom she loves. Lanyard, who has been posing as Victor's Asian butler, and Karslake, both Scotland Yard agents, capture the gang amid fire and fights.