Paris, 1633: Cardinal Richelieu is on his guard. France is under threat, and a secret society is conspiring against him from the heart of the greatest courts in Europe. To counter the threat, Richelieu has put his most trusted men into play: the Cardinal's Blades, led by Captain la Fargue. When la Fargue hears from "La Donna," a beautiful spy claiming to have valuable information, he has to listen. She says the enemy is an exceptionally dangerous adversary: the Alchemist in the shadows.