Plot
On the French-Spanish frontier, a French patrol led by Colonel Leroux of Napoleon's Imperial Guard overtakes a carriage containing a priest and three nuns. The priest is the confessor of El Mirador, Wellington's top secret agent in Spain; he is tortured into revealing the spy's identity. Then, he and two of the nuns are killed, but the youngest, a novice, escapes.
Major Sharpe and his riflemen show up and rout the French, Leroux kills his own captain and swaps jackets to conceal his rank, allowing himself to be taken captive. Sharpe finds a piece of paper on the prisoner filled with cryptic numbers which he thinks is a code, his gut instinct makes him suspect his captive is really the colonel. Sharpe instructs polyglot, rifleman, Harris, to decode the message, but he needs the cipher, a copy of Voltaires, Candide, which Harris has mistakenly destroyed. Sharpe is unable to convince South Essex commander, colonel Berkeley, nor his fellow officer, Captain Jack Spears that the Frenchman is a colonel. Leroux is allowed to give his parole as an officer, allowing him to wander freely amongst the British camp and not be placed in manacles. The young woman, having lost her faith and being rendered mute by the horror she has witnessed, attaches herself to Sharpe.
Back at camp, Wellington's spymaster, Major Mungo Munro, has received word that Napoleon himself has sent Leroux to capture El Mirador. Munro assigns Sharpe the task of killing the colonel, but refuses to divulge the spy's identity. He sends Sharpe and the South Essex Regiment to Vilafranca, the town where El Mirador is based.
The British already control the town, but there is a French-held fort close by. When the men near the town, a surprise artillery barrage (using exploding round-shot) from the fort causes enough confusion to allow Leroux to break his parole by killing a young officer and escape to its safety.
Sharpe meets two people, his old enemy Sir Henry Simmerson, now the British representative to the town, and Father Curtis, an Irish priest, who runs the local hospital.
The regiment attacks that night, but the French have been forewarned and the assault is bloodily repulsed. Berkeley is killed at the outbreak of the battle, leaving Sharpe in charge. As Sharpe gains the top of the wall, he is faced by a ferocious counterattack led by Leroux. After a sword fight with Leroux himself, which ends in stalemate, Sharpe is wounded and demoralised at the loss of his sword. As he leads the retreat back he is shot, but not before commanding Spears to go to Munro for artillery. Sharpe is left for dead, but found by a distraught Harper. Father Curtis says Sharpe will die as the bullet is too deep, surrounded by pus. But the woman tends to his sword wound and removes the buried bullet, staying with Sharpe all night praying or him. Sharpe survives the night but has fever, which forces Father Curtis to take drastic action, helped by the woman and the chosen men they get Sharpe to recover. As Sharpe convalesces, Harper makes a deal with the father, to marry Ramona in exchange for a new sword for Sharpe, a sword which Harper works on to make battle ready. The new sword revitalises the wounded Sharpe.
In the meantime, Harris has found a copy of Candide in the hospital's library and breaks the code. The message unmasks Spears as a traitor (he had been taken captive, tortured, and then blackmailed by Leroux). However, Spears is unable to bring himself to kill El Mirador, who is revealed to be Father Curtis. When Spears arrives with the cannon, Sharpe gives the officer the opportunity for an honourable death, which he gratefully accepts.
Taking advantage of Sharpe's absence in the attack, Simmerson attempts to rape the novice (who had humiliated him earlier when he had made a crude advance), but is stopped by Father Curtis. The priest accuses Simmerson of warning the French of the first attack; when Simmerson advances on him with sword drawn, Father Curtis, an ex-soldier, unexpectedly draws his own and teaches him a very painful lesson.
The South Essex begin another attack. After the fort is softened up by an artillery barrage, the one-armed Spears charges and single-handedly plants the British flag at the fort's entrance, rousing the morale of the British soldiers, but is killed shortly after. Sharpe and the South Essex then storm the fort and win. The officers surrender and ask for parole, which is accepted, but when Leroux tries to surrender, Sharpe offers him a duel to the death instead; if he kills Sharpe, he can go free. Sharpe wins. Father Curtis manages to trick Harper into thinking he is mortally wounded, so he marries Ramona on the battle field, witnessed by all. The woman decides to stay with Father Curtis and the church. Sharpe takes one last look at her before moving on.
