Felix Heidelmann, an egotistical master criminal, is also a master of disguises. He poses as a wealthy man and marries Mrs. Kittredge, a well-to-do widow, then persuades his new wife and her daughter to take a transatlantic cruise with him. When the ship is torpedoed, Mrs. Kittredge drowns and Alice gets amnesia from the shock of her mother's death. Felix disguises himself as "Mr. Groaner" telling Alice that he is her father. Because Martinez, Alice's uncle, recognizes Felix, Felix shoots Martinez through a dining room wall in order to protect his false identity and tries to blame Lloyd, who is Alice's brother, for the murder. Paul Stanton, a clever detective, unmasks Felix and discovers his diary of past crimes. When Paul finds that Alice has been kept hostage in a water-ridden vault underneath Felix's room, he frees her.