In 1844, in the final era of the Shogun, the cruel young Lord Naritsugu (Goro Inagaki) terrorises and brutalises his people, enjoying immunity from the law. He hopes to join the Council of his half brother and with the powers that come with his status, aims to turn his territory into his suffering playing. A secret plan is hatched by insiders to hire a group of samurai to assassinate him. The leader is chosen first, Shinzaemon (Koji Yakusho), who gathers 11 other samurai through his nephew Shinrokuro (Takayuki Yamada) and a network of connections. They are also joined by a forest dwelling young warrior, Koyata (Yusuke Iseya). The 13 men make plans to ambush Naritsugu and his men during a long journey to a clan across the land.