Wellington's intelligence chief, Major General Ross, is unconvinced, as his spies have reported no discontent in the region, but agrees that a brigade can be sent as a probe if the comte can provide a secure base; he offers a family castle, though he admits that it is garrisoned.
Disgusted, Sharpe and his men gain entry to the castle at night by a ruse, pretending to be a French patrol bringing in a seriously wounded soldier, and capture the place easily.
Sharpe's patrol ambushes and annihilates a French column of reinforcements, capturing a resupply cart and a doctor bringing quinine for the comte's mother.
During the incident, they question the locals and find them fiercely loyal to Napoleon, making them suspicious of the comte's claims that the region is ripe for rebellion.
Under a flag of truce, the comte reveals himself to be Napoleon's agent, and offers to let the British go free, provided that they leave Sharpe behind; Robinson replies for them all, "Fight them to the finish, sir."
Earlier, out of gratitude for Sharpe providing her mother with quinine, the comte's sister had told them to burn a cellar full of oyster shells to produce lime.
With the British ammunition running low, Sharpe's men dump powdered lime from the walls, blinding their foes as they break into the castle.