The good ship Cape Farewell is steaming out to sea, with a passenger-list and crew fairly littered with the shifty, the twitchy, the peculiar, and the up-to-no-good. Arguably the up-to-no-goodest is a strangler with a romantic streak: He likes to leave his ladies with a flower and a charming little song. The latest of the ladies is currently lying on a fogbound London dock, mute witness to the fact that Inspector Alleyn -- long on the strangler's...