Spain, the 1620s of the 17th century. The main character of the novel, Diego Alatriste, is a soldier of the Spanish army who earned the nickname “captain” for his bravery; in peacetime he is a hired killer and a duelist. Having taken in the son of a dead comrade, he is tasked with carrying out a simple assignment by very high-ranking people—to kill a certain young Englishman and his companion, who have recently arrived in Madrid. But this job becomes fateful for Diego Alatriste’s life and for his young ward as well.