At the end of the Edo period, there had been no war for 250 years. Some of the poor samurai chose to leave their vassal states and become wandering samurai or ronin. Tsuzuki Mokunoshin (Ikematsu Sosuke) was one of the wandering samurai. He came to a farmer's house in the suburbs of Edo to help with work in exchange for food. In order to prevent his swordsmanship from becoming increasingly rusty, he practiced every day and taught swordsmanship to the farmer's son Ichisuke (Maeda Takashige) with a wooden sword. Ichisuke's sister, Koyu (Aoi Yu), always treated them coldly because they were keen on swordsmanship all day long, but she and Mokunoshin gradually developed feelings for each other. At that time, due to the arrival of foreign black ships, Japan demanded that the shogunate end its policy of isolation, and the long-term peace began to show signs of unrest. What Koyu was most worried about was that Mokunoshin would go to the central government to participate in the turmoil, which meant that the day when he and his brother would lose their lives was approaching.