The Lone Wolf, an international thief who is expert in dodging the police, is rifling a wall safe when he senses the approach of detectives. Secreting a necklace in a cigarette case, he makes a hasty retreat. In disguise, he climbs to the balcony of another house where a bal masque is in progress and conceals himself in Marcia Mayfair's boudoir. Later he mingles with the guests and dances with Marcia. Lanyard is disclosed as a stranger when detectives force the guests to unmask, but Marcia remai...