Rarely do magicians reveal their professional secrets. Consequently Frank and Joe Hardy are amazed whena well-known magiician, the Incredible Hexton, offers to reveal the secret of his "Vanishing Man Act" and invites Mr. Hardy to be the subject. When their detective father fails to reappear, his sons are convinced that something sinister is afoot, despite Hexton's insistence that Mr. Hardy is playing a joke on them.