In this book we find Cornwell's Richard Sharpe, a soldier in the Napoleonic era, fighting the French in the Peninusular War. At the outset he executes two captured French soldiers who have raped a girl, and this leads to a prolonged feud with their commander, one Brigadier Loup. It also nearly results in Sharpe being cashiered when he reveals what he has done. As usual in a Sharpe novel, there is plenty of action: Sharpe is attacked by Loup and his men in a crumbling Portuguese castle he is garrisoning and barely escapes with his life; later he is caught up in the battle of Fuentes de Oñoro, which Wellington came close to losing. Finally Sharpe fights a duel to the death with Loup.
Cornwell is particularly good at describing battle scenes and those depicted here are well up to standard. As often happens in these Sharpe novels, however, there are improbabilities that jar on the reader—this reader, anyway. Take the language used by the characters. All of them - English, French, Spanish, Portuguese—speak in the same way, using fairly modern English at that, even in the case of a very rough Partisan known, appropriately enough, as El Castrador. In his case we are told that he speaks in Spanish, as he obviously would, but Sharpe appears to be able to converse with him without difficulty, as he does with everyone else, including Loup's mistress, a sultry Spanish noblewoman called, slightly oddly, the Doña Juanita (Doña Juana, without "the", would be more authentic). She eventually shoots Sharpe, not fatally of course, in a vain attempt to save her lover Loup; I found her somewhat unconvincing.
There is also a constructional problem with the story. Generally in this series we see events entirely through the eyes of Sharpe, but here there are a couple of occasions on which we encounter Loup, Juanita, and others without Sharpe being present. I'm not sure that Cornwell gets away with this; the narrative convention is strained pretty well to breaking point here. Provided one overlooks such things the book works well enough, however, and Sharpe aficionados will definitely want to add it to their collection.