After discovering his older sister has been inexplicably murdered, D’Eon de Beaumont joins the French secret police–which has been investigating the disappearances of numerous young women–in hopes of solving the mystery of her death.

D’Eon’s battle against Vorontsov is finally finished, with Lia dealing the final blow. The Four Musketeers follow Robespierre to London.

The Four Musketeers meet with the French Ambassador to England, and they attend a party thrown by the English king and queen intending to steal important documents held by the British Undersecretary of Foreign Affairs.

Lia continues reciting Psalms until Teillagory calms her down. King Louis receives copies of Robert Wood’s documents.

The Four Musketeers obtain the Psalm of Kings. Durand goes to the French Embassy, attempting to return to France alone so as not to have to kill his comrades.