Fictional life of French King's personal assassin who commits six murders, his love affair, struggle with his conscience and death on the guillotine. Jean Louis Valmont, son of groom in Royal Stables, taken up and cultivated by King Louis XV. Once grown, in early career Valmont murders a duchess and a countess, both mistresses of King who get in monarch's way, later the King's son for politics, daughter-in-law to cover crime, the Queen to sexually free up the King, and the King's personal valet who annoys Louis XV. Story is also of Valmont's love for Juliette Beauvoir, a chambermaid who is raped but later seduced by Duc de Richelieu, as well as Valmont's friendship with Madame de Pompadour and his services to Madame du Barry, both mistresses to Louis XV. After the King's death Valmont tries to come to terms with what he did, including seeking out the writer Voltaire. Eventually he falls into the hands of the revolutionaries and is reunited with Julie after many years. He meets the soon to be executed last bastard son of Louis XV and though to be set free, changes places with young man and dies in his place. The subject of the book through its presentation of the characters is France itself and covers the years from 1723 until 1794.