Time: the 1930s, Take one stately English home - complete with secret passage and impeccable butler. Fill with assorted characters gathered for a weekend house party. Among them, an eccentric, gun-crazy earl; his brother, a government minister engaged in top secret talks with a foreign envoy; a Texas millionaire and his wife (the owner of a fabulous diamond necklace); a young lady down on her luck; and the uninvited guest - a beautiful European adventuress, complete with shady past and unconvincing present. Add: the threat of a visit from 'The Wraith', notorious society jewel thief; a violent thunderstorm; a fight in a darkened room; a scream in the night - and a body in the lake. Finally, season with one highly unconventional detective. A superb puzzle of the Agatha Christie genre.