Sharpe's Sword is a novel in the series that chronicles the heroic exploits of Richard Sharpe. In this novel, Sharpe takes part in the British campaign to drive the French from Salamanca, and in the process he meets a beautiful woman and faces a deadly adversary.

The story begins with the capture of Colonel Philippe Leroux, a special agent of Napoleon who uses torture to extract information from civilians. Leroux's particular method of torture is ghastly. He slowly strips the skin from the victim until he gets the information he seeks. Afterward, to instill further terror, he carves "Leroux made this" on the bodies of his dead victims. Leroux carries a Kligenthal sword that is the finest Sharpe has ever held. At the opening of the novel, Leroux has just finished torturing and killing a priest before the arrival of German cavalry forces him to flee.

Leroux is captured by Sharpe's Riflemen, but through guile he manages to escape. In the process, he kills a sixteen-year-old ensign and Sharpe's commanding officer, Lieutenant Colonel Windham. On a personal level, Sharpe vows to get revenge. On an official level, because of Sharpe's firsthand knowledge of Leroux, Sharpe is tasked with his recapture.

Along the way to meeting Leroux and fulfilling his duty as leader of the Light Company, Sharpe meets a variety of unforgettable characters. Father Patrick Curtis is an Irish priest and professor at the Irish College in Salamanca. He has an entertaining wit and a knack for seeming to be in places at crucial moments. Captain Jack Spears is a young aristocrat and Exploring Officer. He is fun loving to the point of complete irresponsibility, and he is as likable as any character in fiction. Helena is a wealthy blond marquesa who takes a fascination in Sharpe and the stories surrounding his past heroics. She is the most beautiful woman Sharpe has ever seen, and she possesses an intellect equal to anyone Sharpe has known. Each of these three characters has dual identities, and the surface identity, the one Sharpe initially knows, is far different from the one he knows by the conclusion of the novel.

In his second meeting with Leroux, Sharpe is wounded and even believed dead for a while. Sharpe's many friends rally to his support, particularly his sergeant and best friend Patrick Harper. Harper also has some memorable exploits through the course of the novel. At one point he is mistaken for an insane grave robber, and days later he is trying unconventional remedies to improve the health of his injured captain. All characters who know Sharpe are deeply affected by his brush with death, and most are overjoyed with his miraculous recovery.

Despite his injuries and vulnerability Sharpe refuses to follow orders, and long before he should, he sets off in pursuit of Leroux. The action is non-stop, and many mysteries remain until the very end.