A mysterious coin found at a murder scene stirs the curiosity of young actress detective Oshichi and her brother Hyoma, who set out on a private investigation to unveil the secrets hidden behind the coin.

Yagyu Jubei must protect the Yagyu scroll that holds the secret of the infamous assassination plotted by the Tokugawa government 30 years ago.

In the fifth installment, Yagyu Jubei must prove the innocence of his family who is suspected of conspiring to take Shogun's life.

The mysterious black hooded man, Kurozukin, helps transport funds raised to fight against the government.