When the Duke of Purbeck throws a house party to celebrate his daughter's 21st birthday and present her with a family heirloom, nobody expects that the weekend will end in murder. The fabled Belsingham pearls have a history steeped in blood and slaughter dating back more than a century - and now it seems they've claimed another life, when the interfering and opinionated Professor Coddington is found dead in the library with the pearls clutched in his hand.
It looks like a robbery gone wrong, but then why didn't the thief take the necklace? And how did he escape unnoticed, given that half the guests were seemingly wandering around the house at the time of the murder?
House guest Freddy Pilkington-Soames has enough on his plate already, with a lecherous nuisance of a grandfather to keep an eye on, a girlfriend his mother disapproves of, and an ex-girlfriend who's engaged to another man but shows signs of changing her mind. But with a killer on the loose in the house, it's time to forget his own troubles and rise to the occasion - or risk a scandal that could destroy the reputation of his whole family.