Leopold Kroner, formerly of Colby Enterprises, is released after five years in prison for embezzlement. Andrew Colby, claiming that Kroner has threatened him, hires lawyer Bob Regan as a secret bodyguard. Sure enough, Kroner turns up in Colby's room with a gun, and Regan kills him. Then Regan, who sticks around to romance Colby's secretary Noel, begins to suspect he's been used.
For her first day of orientation, Dr. Tristian Mackenzie makes her way to the Silverdale Psychiatric Hospital for the criminally insane, where she learns of the strange series of cases from the similarly strange Dr. Moon.
