In August 1811, George, Prince of Wales and the Prince Regent is horrified to find his mistress Sarah, Marchioness of Creeve dead in his bed, strangled by the string of pearls around her neck. The Prince realises what a scandal could come out of a dead married woman (not to mention his younger brother's mistress) so he has Tam Eildor, masquerading as a Scottish lawyer, investigate the murder.

Tam's investigation is interrupted by an attempt on his life - and the Prince's discovery that the Stuart Sapphire has gone missing.

Tam's search for the killer and the thief puts his life in danger. Amidst a cast of royally quirky, entertaining, and psychologically complex characters, Tam needs to figure out his purpose in the Prince Regent's service, find the killer thief, and get home before time does away with Tam's memory of home, or someone does away with Tam.