In 1579, a Portuguese trade ship sails into port at Kuchinotsu, Japan, loaded with European wares and weapons. On board is Father Alessandro Valignano, an Italian priest and Jesuit missionary whose authority in central and east Asia is second only to the pope's. Beside him is his protector, a large and imposing East African man. Taken from his village as a boy, sold as a slave to Portuguese mercenaries, and forced to fight in wars in India, the young but experienced soldier is haunted by memories of his past. From Kuchinotsu, Father Valignano leads an expedition pushing inland toward the capital city of Kyoto. A riot brings his protector in front of the land's most powerful warlord, Oda Nobunaga. Nobunaga is preparing a campaign to complete the unification of a nation that's been torn apart by over one hundred years of civil war. In exchange for permission to build a church, Valignano "gifts" his protector to Nobunaga, and the young East African man is reminded once again that he is less of a human and more of a thing to be traded and sold. After pledging his allegiance to the Japanese warlord, the two men from vastly different worlds develop a trust and respect for one another. The young soldier is granted the role of samurai, a title that has never been given to a foreigner; he is also given a new name: Yasuke. Not all are happy with Yasuke's ascension. There are whispers that he may soon be given his own fief, his own servants, his own samurai to command. But all of his dreams hinge on his ability to protect his new lord from threats both military and political, and from enemies both without and within.