The winter of 1578, four years prior to the Honnnoji Incident. Araki Murashige has betrayed his ally Oda Nobunaga and holed up in Arioka Castle—but a string of strange incidents within the castle walls has him at his wits' end. The desperate warlord's only hope in solving these mysteries is imprisoned in the castle's dungeon: a man named Kuroda Kanbei, one of Oda's most gifted strategists. When all the conflict and intrigue reach their end, what will Murashige and Kuroda have up their sleeves?