Ameer Ali, a Pathan, is adopted by a Thug named Ismail and becomes a Thug himself. In prison, Ameer Ali confesses his life story as a devoted follower of Thugee, a secret cult that practices ritual murder and robbery, to a British officer. The novel introduced a new standard of ethnographic realism to Western fiction about India and provided vivid and chilling details about the crimes of Thug bands in India in the 1820s based on evidence collected by the novel's author as a police superintendent. It became a bestselling crime novel and influential work about British India in the 19th century.