Mr. Pottermack, wrongly convicted for forgery of checks, has escaped from jail, made his fortune in the US and come back to England to find his fiance. The only one who is cleverer than Mr. Pottermack is Freemans detective, Dr. Thorndyke. In this novel, the sympathetic, engaging and enterprising Mr. Pottermack commits the perfect crime, only to discover that a perfect crime is the last thing in the world he wants. Then Mr. Pottermack comes up against the legendary Dr. John Thorndyke, physician and lawyer, the dean of scientific detection, who seems to know far too much about what Mr. Pottermack did on a night when there was nobody around to see him. Will Dr. Thorndyke celebrate another triumph? Or will Mr. Pottermack avoid detection and finally find happiness?