A thick fog envelops London. A mysterious killer strangles several men in the shadowy streets. We learn the killer is targetting officers in a particular WWI unit. The setting shifts to a manor house. Roland Young delivers a charming, wry performance as the story settles into a closed-circle mystery. Then Dorothy Sebastian and Boris Karloff burst in. Sebastian over-emotes and struggles to maintain her ludicrous accent. Karloff struggles with his own invented accent and looks lost. The tonal shift proves fatal as the film limps along to an elaborate climax with a cheat ending. Great title, poor execution. The archive.org print—sourced from TCM—is passable.