Nero is a young man who works in the island castle-town of Fortuna for The Order of the Sword, a sect of holy knights who revere the demon Sparda and are led by their benevolent spiritual leader Vicar Sanctus. During the Festival of the Sword, Sanctus is murdered by a mysterious man in a red coat who then escapes, Nero is tasked with finding the unknown figure and sets out to trace his steps but over the course of the search he encounters with the dark side of the Order.