At the start of the industrial revolution, feudal Japan is in chaos as the ruling Shogun are viciously abusing their power. They instill fear and control over their oppressed subjects by means of beatings, imprisonment, rape, and even murder. This violent reign must come to an end. A group of Samurai have united, equipped with new weapons and technology, and the determination to fight back. Ichimatsu is one of these warriors. Concealing his identity, he works at a local tavern by day, attends brothels at night, and administers powerful justice with his gun under the cover of darkness. He is a hero, known as Samurai Gun, who has arrived to aid in the rebellion.