Gathering a band of 13, Inspector General Shmada Shinzaemon sets out on a death-defying journey to cut down the shogun’s half-brother, Matsudaira Naritsugu.

Yataro Tanigawa, a one-eyed hired assassin, impresses yakuza boss Gomyo Kiyoemon with his skill. Gomyo hires Tanigawa as his bodyguard, or yojimbo, to protect him during an inter-clan conflict. Tanigawa quickly rises in stature in the clan, but finds his boss's enemies almost overwhelming.

A cynical samurai is left as the sole survivor to fulfill a plot to assassinate the puppet of a villain intent on usurping the shogunate in the 17th century. A Shogunate Elder connives to rule Japan by making his puppet, the Shogun's brother Tsunashige, the next Shogun. The best strategist in Japan, Yamaga, leads a plot to stop the Elder, but his cabal is betrayed and most of the conspirators are captured and tortured.