In the continuing adventures of Nemuri Kyoshiro, noted film actor Tamura Masakazu stars again as the red-haired ronin with foreign blood in his veins. The son of a foreign missionary and a samurai's daughter. His mother died when he was a child, and he was forced to bury her himself, praying that her soul would rest in peace. He became an expert at swordsmanship, despite being in the shadow of isolation and nothingness, and walks the bloody path of destruction carrying his only friend, a razor sharp sword made by the Master, 'Peerless Masamune' to go with his unique Full Moon Sword style. After being accused of being a government spy, he falls ill and accepts the aid of a prostitute who nurses him back to health. As he prepares to leave the Chief Retainer of the Akita Clan asks him to help save the clan from an evil plot. Kyoshiro's deadly full moon cut will have to come into play against many who seek his life!

Kyoshiro rescues Shizu who was being abused by her husband, even since she had been violated by the man posing as Ieyoshi. He then learned that Ieyoshi had been acting oddly ever since returning from Kyoto six months ago. Sir Fumiya's investigation of the O'oku (Shogun's harem in Edo Castle) uncovered the plot and reported that Sir Higo-no-Kami had been controlling the fraud. That's when Kyoshiro heads to Kyoto to find clues...

Sakai Nobunari an Elder in 'Honmaru' (or the main enclosure) and Mizuno Tadakuni an Elder in 'Nishinomaru' (or the south-east enclosure) have been at odds behind the scenes over the marriage of Tokugawa Ieyoshi, heir to the Shogunate. Kyoshiro, who has come back in Edo after 3 years is involved in it against his will. It's because he gets to know Lady Mihoyo who is a spy for Sakai and looks exactly like his late mother. As she couldn't complete her mission she has nowhere to go. Kyoshiro shelters her from both parties that seek her life. The original story is from "Nemuri Kyoshiro Burai Hikae" written by Shibata Renzaburo. Not only is one of Japan's greatest legends kept alive, but some secrets of Kyoshiro's past are finally revealed for the first time.

Tamura Masakazu returns as Nemuri Kyoshiro for the fourth and final time. Gensai, an eccentric Ukiyoe artist, urgently requests Kyoshiro to kill his wife. He believes that the moment she is killed will represent the ultimate state of beauty, and wishes to see Kyoshiro's signature “Engetsu Sappo” (“Full Moon Cut”) killing technique for the purpose. But this unusual request comes not only from Gensai, but also his wife, Orin, who has a tie to Kyoshiro's past. Meanwhile, Tenzen wants to hire Kyoshiro as their master sword instructor for the Kurume Clan, whose lord has an unhealthy obsession with Kyoshiro and his Engetsu Sappo…