During a house party at the Copeland residence, hypnotist Norman Osgood entrances guest Harrison Kirke. Upon waking from his trance, Kirke becomes so angry that he threatens Osgood's life. The hypnotist then secretly provides George Clayton with a suggestion to kill Kirke "one hour before dawn." The next morning, Kirke is found murdered, and Clayton recalls a terrible dream in which he had killed Kirke, leading him to fear that he committed the crime while sleeping. When the detective arrives to investigate, Clayton's fears cast suspicion upon him, but after several false leads, the detective finally unmasks the real killer as Bob Manning, an old enemy of Kirke's.