A pro-Bourbon Noble, the Compte de Maquerre is in Wellington's camp, arguing that Bordeaux is ripe for rebellion, but Maj. Gen. Ross is dubious. He suggests using the Compte's castle, 60 miles behind ene...展开my lines, as a base. Maquerre is reluctant, saying his mother and sister had turned it over to Napoleon, so it must be captured. Col. Horace Bampfylde is to lead the attack, with Sharpe in support.
There is sickness in the camp and Maj. Gen. Ross and Sharpe's new wife, Jane, succumb to it. The only cure is quinine which is in short supply. When they reach the castle, Col. Bampylde wants the glory, he sends Sharpe, Capt. Frederickson and the Rifles scouting, so he can take the castle alone. He fails in his mission, but gains heavy casualties.
Sharpe sees what is happening from afar. He infiltrates the camp and forces the French to surrender. Bampfylde returns to the castle and sends Sharpe and his men away. Maquerre returns with the mayor. They tell Bampfylde that the region has changed sides, Gen. Calvet is on his way and Sharpe is dead. Bampfylde is persuaded that he has accomplished his mission and returns to tell Wellington.
Sharpe and his men ambush a French convoy and capture a small supply of quinine. He also finds out that the region is far from ready to rise against Napoleon, and concludes that Maquerre is a double agent. When he returns to the castle, he finds it deserted except for the wounded, along with Maquerre's sister and sick mother. Gen. Calvet is heading towards the castle, and Sharpe and his men are desperately short of ammunition.