Millie Trent, the toast - or scandal, according to some - of a West Country sailing resort, is found drowned. The verdict is accidental death, although no one seems to know when or why she ended up in the sea. Paul Mycroft, despite his determination not to let the affair spoil his family holiday, finds himself drawn into an enquiry that begins by providing a startling diversity of views on Millie's character and ends by involving him in unexpected danger.