Dry wit and nautical lore run through this mystery Lady P is a scientist, inventor and engineer - but above all she's a fun-loving and youthful grandmother. But she doesn't see the funny side when the dead body of a youngish woman turns up on board her daughter's sailing boat. Even Inspector Plummer cannot prevent Lady P's natural inquisitiveness landing her in deep water - and in hospital. But gradually clues surface with very unpleasant ramifications for all concerned.