France 1813 - The war is entering its final stages and the French formulate a desperate plan to capture Wellington's spy master, Major General Ross. Sharpe is ordered by Wellington to accompany Colonel Brand, who is intent on destroying the French's main powder supply in the caves of Rocha. Wellington and Ross are both suspicious of Brand's loyalty, but they do not reveal this to Sharpe. The suspicions are well-founded as Brand secretly meets with the French and makes plans for capturing Ross. On the home front, Sharpe's wife is showing signs of being bored with army life and enjoys the attentions of a young poet.