Until her children stumble upon the body of the Hon. Lewis Thornsby in the wings of the Tavistock Theatre. Suddenly, Mélanie and her husband, Malcolm, plunge into an investigation that cuts closer to their former life of espionage than they would have thought possible. Thornsby, a seemingly guileless young man about town, was part of the Levellers, a secret group of reformers whose leader is a friend of the Rannochs. A paper on Thornsby's body hints at a plot to assassinate a member of the royal family.

Was Thornsby the would-be assassin or was he killed because he had learned too much? Is the plot genuine or an attempt to entrap and discredit the Levellers? As their investigation takes them from gin-soaked Covent Garden alleys to Mayfair drawing rooms, the Rannochs learn Lewis Thornsby was not at all what he seemed. Whether his death is tied to the assassination, the pretty young actress he was willing to give up his fortune for, or his unexpected links to the Continent, someone was very determined he take his secrets to the grave. And if Mélanie and Malcolm can't uncover those secrets, their fate (along with that of their closest friends and Britain itself) may be in deadly peril.