A young Tokugawa Mitsukuni (Yamamoto Koji) meets a homeless orphan Ryosuke (Kurokawa Souya). Surprised by his deadly skills with a wooden sword, Mitsukuni invites him to the covert organisation known as Juninshu. The members of Juninshu are orphans with outstanding skills. They conduct intelligence work using their special abilities and help to capture criminals. With the help of Juninshu, Mitsukuni discovers that Nishiki Hyonosuke (Kato Shigeaki) is the leader of the gang of arsonists that caused the Great Fire of Meireki. Hyonosuke is the son of Unkei (Ishizaka Koji), a sculptor specialising in Buddha statues whom Mitsukuni admires. Unkei has lived to bring Hyonosuke, who has gone off the right path, to justice with his own hands. Hyonosuke aims to overthrow the Tokugawas and a fierce battle is imminent. Worried for Mitsukuni, his wife Yasu (Matsumoto Honoka) seeks the help of the great swordsman Yagyu Gisen (Tachi Hiroshi)..