Hotaru Kunoichi, hailing from Iga Village, took on a task to infiltrate Aduchi Castle, the property of Oda Nobunaga. Akechi Mitsuhide, a close associate of Nobunaga, awaited her arrival. Pretending to be his sibling, Hotaru gains access to the castle and begins examining the attitude of the Oda army to detect any potential threats to Nobunaga. Hotaru forms close connections with powerful military figures, including Nobunaga, Hashiba Hideyoshi, and Tokugawa Ieyasu, but her true identity is in danger of getting revealed, putting her entire operation in grave danger.