At the end of the feudal era, when the West began to influence the culture of Japan, Raizo is ordered to assassinate an important businessman, accused of trafficking opium and poisoning the population.
Raizo is an experienced samurai, incredibly loyal to his clan, to the point that he does not hesitate to carry out his mission, even though the target is his own father-in-law.
Traumatized by killing him, Raizo remains in town, hiding and hesitating to return home, where his fiancée should have received the news of his father’s death.
One day, Yuen, who claims to be doing personal jobs, approaches Raizo and begins to ask him some questions. He tells him that his father-in-law hired him to do a special job, in case he lost his life.
Yuen tells Raizo that the best thing he can do is return to his home, face the situation and continue his life. Raizo thanks him for his words and begins a new journey, but on his way he is intercepted by some members from his own clan, who end up betraying him.
Before he is killed, Raizo listens a voice telling him to jump into the river, and without hesitation he does it. At that moment he is shot, but despite this he is able to survive, thanks to the help of Nio, a collaborator of Yuen.
When he wakes up, Yuen confesses to Raizo that his father-in-law was not the person trafficking opium, actually, he was investigating the case and was about to discover the culprit.
Raizo can’t believe what has happened, at that moment, Yuen tells him that in addition to selling different types of crafts, they do all sort of special jobs.
Yuen asks Raizo to support them in ending the opium trafficking, because one of the leaders is in his own clan. Raizo agrees to help and they set off on the journey immediately.
In order to enter the criminal’s stronghold, Yuen asks Raizo for details, asking him to wait and avoid getting involved. However, Raizo takes advantage of the attack by Yuen and his collaborators to ambush his former boss, and without hesitation ends his life.
Finally, Raizo decides to go and face his fiancée, who is said to be devastated by losing her father and, apparently, her fiancé as well. But once he enters her property, he discovers that she has committed suicide, leaving the samurai alone in the world.
An original anime series animated by Ajia-do Animation Works and produced by Nitroplus and Shochiku. It began airing on January 5, 2023.