New twists, ideas, and the use of off-timing, this successfully handles few characters, minimum action and maintained suspense. Dr. Riordan, after rising cat-and-mouse approaches, contrives the successful murder of his wife's lover, but his area of safety is diminished when his wife sides with Scotland Yard to get his confession. But a confusion of last minute finesses keep the Inspector on the case from learning the whole truth of the affair. Bright, tricky.