Christopher receives a letter from Eloise Dauvray requesting him to call on her and meet the other of the only two real men she has ever known. He goes and meets Prince Mirko of Dalvania, who is planning to regain the usurped throne of his father. The prince has become secretly engaged to Eloise, and does not want the fact known, because Rudovois, the Dalvanian Ambassador, has promised the prince his aid provided the prince marry his daughter. Fitzgerald, an old enemy of Christopher and Eloise, learns of her engagement and sees a chance to profit by it. He tells Rudovois that the prince is about to marry Eloise and suggests that they make off with Mirko and hold him till Eloise is willing to give him up. The ambassador reluctantly agrees and the prince is kidnapped and hidden. Christopher begins to suspect who is responsible. He discovers that Peter, Mirko's brother, is in love with Valda, the ambassador's daughter. He suggests a plan whereby Peter and Valda elope, leaving no word. This affects Rudovois, who loves his daughter dearly, so that Christopher easily gets a confession from him. They go to the rescue in the Scarlet Runner, which by its superior power and speed, once again wins the day for its owner and his friends.