In 18th century Paris, a coffin containing the corpse of noblewoman Lia de Beaumont is discovered floating down the Seine River. She was a spy for King Louis XV and her younger brother Charles dEon has just been knighted. After several mysterious disappearances occur in Paris, dEon suspects that they are connected to his sister's death. To investigate, he joins the secret police.
Through careful analysis of evidence, dEon discovers a conspiracy between members of the French and Russian nobility, driven by a cult. He concludes that Lia may have uncovered the truth while on a mission and was killed as a result. That night, the secret police plan to arrest the Duke of Orléans for his suspected role in the disappearances.
However, one of their own transforms into a demon called a Gargoyle and massacres the group. dEon tries to save the sole survivor but is also transformed. During the ensuing battle, dEon's body is possessed by Lia's vengeful spirit, who takes control and slays the Gargoyle herself.
In the aftermath of these events, dEon must gather allies to uncover the full extent of this supernatural conspiracy.
Miwako Okuda
Aya