All but forgotten in Great Britain, where it was made, and essentially unknown here in the states, this decidedly peculiar and clever murder mystery stars the criminally underrated, German-born leading man and character actor Peter Van Eyck. It is a tense and unpredictable B&W thriller that deserves greater acclaim, and should be appreciated by all fans of well-made suspense flicks. The exact title remains a closely guarded secret until showtime.