To catch a thief, a detective has himself committed to a high-class asylum. The orderlies do not need a straitjacket for Bill Crane. He is not violent, although he does have a bad habit of making embarrassing deductions about the doctors. This sarcastic, hard-drinking man has deluded himself into thinking he is Edgar Allan Poe's great detective, C. Auguste Dupin. For this, he has been put away in a stately mental hospital on the Hudson. But Crane is not as delusional as he appears. Though he may not be Dupin, he certainly is a detective - one of the greatest, and occasionally drunkest, of them all. Sent undercover to investigate the theft of an inmate's fortune, Crane finds the institution not as comfortable as he had hoped. When his fellow patients start dying, he must solve the murders, or risk losing his sanity after all.