Cádiz, 1811. While the city is under siege from the marauding French army, an even greater menace is lurking within the city walls: a serial killer is on the loose, flaying young women to death. Each of these murders takes place near where a French bomb has just fallen. In order to find the murderer, police commissioner Rogelio Tizon begins to perceive the city as a vast chessboard as he tries to predict his unknown opponent's next deadly move. In the claustrophobic atmosphere of the besieged town, an heiress, an unscrupulous corsair captain, a taxidermist who is also a spy and a hardened soldier begin to cross paths, and behind them all the figure of Tizon is getting closer to deciphering the lethal pattern behind the murders...