The 21st instalment in Shintaro Katsu's Zatoichi vibrant series of samurai action films. Blind swordsman Zatoichi (Shintarô Katsu) is on his travels again. When he witnesses an auction where women are sold to the highest bidder, Zatoichi rescues a beautiful woman from her fate - but in doing so, he incurs the wrath of her sex-starved buyer (Tatsuya Nakadai). He also comes up against the Yakuza Boss of all Bosses, Yamikubo (Masayuki Mori) - aka 'the Prince of Darkness' - who turns out, like Zatoichi himself, to be blind. Yamikubo tries everything he can to get rid of Zatoichi, who stands in the way of his corrupt and extremely lucrative tax-collecting schemes. When assassins fail to kill Zatoichi, Yamikubo lays a complex and powerful trap with a beautiful young woman (Reiko Ohara) at its centre.