The game opens with a narration by William describing Amrita, a mystical golden stone found in abundance in Japan that is sought by the government of Queen Elizabeth I to secure victory over Spain. William is held in the Tower of London, but breaks out with the help of his Spirit Guardian Saoirse, a being born from the prayers of his home village who saved him from death when he was a boy and now prevents him from dying. William corners Edward Kelly, who is seeking Japan's Amrita. Capturing Saoirse with his own Ouroboros spirit, Kelly uses her to find Japan, with William going in pursuit. Landing in Japan in 1600, he fights Oni that are ravaging the area, catching the attention of Hanzo Hattori.