The Franco-Spanish Frontier, 1813: although the French army is in retreat from Spain, Napoleon is planning a surprise counter-attack. To succeed, he must flush out and capture Wellington's master spy, El Mirador. Sharpe is sent to protect El Mirador from the French Colonel Leroux - one of the "Boney's Best" swordsmen and personally chosen by Napoleon for the job. The danger of the mission becomes clear to Sharpe when he finds himself in a fight for his life against the accomplished Leroux!