Herr Ludwig Kronitz is a king in his own works and rules with a controlling hand. He is known as the "Man of Iron." He has made a fortune out of the manufacture of guns, and is hard and unscrupulous. His character is shown by various little incidents around the factory. His daughter, Hilda, returning from a trip to America, meets John Smardon, a well-to-do young American, partner in some steel works. They fall in love, but Hilda does not hold out much hope, as she knows her father has other ideas. Carl Heiner, a workman at Kronitz's place, who has an invalid wife, has invented a new machine gun. Heiner tells his plans to Bopp, a tool of Kronitz. Kronitz sends for Carl and offers to buy the invention at a small price. Carl refuses and Kronitz then gives him the choice of selling or being discharged. He refuses. He cannot get work and he and his wife are in great distress. Half crazy with desperation, he goes to the works at night, meets Bopp. and, in a frenzy of rage, attempts to hurl him into one of the furnaces, but is frustrated by other workmen. He is sentenced to prison. When Carl is released, he finds his wife dying. He casts the dust off the place from him and wanders forth, swearing vengeance. Kronitz having received an offer for his daughter's hand from a duke, rejects John's suit, but Hilda, while she will not marry John without her father's consent, says she will be true to him. John picks up Carl, fainting by the roadside, hears his story, and takes him with him to America, to his works. There, he patents Carl's invention. Kronitz, meanwhile, with the help of Bopp, and some experts, has reconstructed the gun, and comes to New York to interest American capital in it and make a fortune, but the tables are turned when he finds the gun already patented, and is brought face to face with Carl, and vanquished. He gives up the fight, admits Carl's rights to the gun, and to save himself, gives his consent to Hilda's marriage with John Smardon. Carl, for the sake of Smardon's friendship, forgives Kronitz and tries to forget his injustice.