June 1820. Britain's former prince regent, now George IV, is determined to divorce his estranged wife, Queen Caroline, and the coming trial is the talk of London, from Mayfair to Westminster to Seven Dials, dredging up scandalous details and pitting Whigs against Tories in a battle for power. When former spies Malcolm and Mélanie Rannoch learn their enemies in the mysterious Elsinore League are trying to sell letters that could prove key at the trial, the Rannochs are determined to intercept these vital papers before they can be used against Queen Caroline.
The exchange is to take place in the candlelit splendor of Carfax House, at the first ball Malcolm and Mélanie's friends Julien and Kitty are giving in their new roles as Lord and Lady Carfax. But Malcolm and Mélanie aren't the only ones determined to intercept the letters. Amidst a night of champagne and waltzing, Mélanie and Malcolm find themselves entrapped in an intrigue that may be as deadly as any they faced in the Napoleonic Wars...