The criminal underworld can probably relax now because “Lord Peter Wimsey” (Robert Montgomery) and his crime-author fiancée "Harriet" (Constance Cummings) are getting married—and retiring their detective work. That is, until they reach their new/her previous home, where a corpse greets them as soon as he carries her inside. The deceased turns out to be “Noakes,” the man from whom “Lord Peter” purchased the place, and…