In the Reign of Terror: The Adventures of a Westminster Boy is a novel by G. A. Henty published in 1888. The novel follows the adventures of Harry Sandwith, an English boy sent to live with the Marquis de St. Caux during the height of the French Revolution.Harry Sandwith, a sixteen-year-old English boy, is sent to live in France with the Marquis de St. Caux, a friend of a French nobleman Harry's father once served. The marquis is impressed with the English system of schooling and believes that his two sons, Ernest and Jules, will benefit from the influence and friendship of an independent and manly English boy. Harry, who is an undistinguished student at Westminster School, is eager for the opportunity to live in France, which he believes will create greater opportunities for him when he joins the British army. Harry sets off for Paris in 1790 with the intention of living with the St. Caux family for the next two to three years.