A masochistic mobster meets his match in the dark streets of Tokyo. His nemesis, Ichi, is a psychopathic killer with an unrelenting thirst for bloodshed. A horrifying secret burns in his mind, and his hands deal death without mercy. At last, the shrouds of mystery are parted to reveal the origin of the monster. The city will know its greatest fear at the unveiling of Ichi the Killer.

The 31st year of the Showa Era (1956) marked the tenth year since Japan's defeat in World War II. It was when Japan took its first step out of post-war poverty to rejoin the international community. In old downtown Tokyo, a teacher and her students try to pass down Doyo (Japanese traditional children's songs) as the root of Japanese cultural identity to the future generations.

Denji is a young man who makes a pact with a demon and ends up working as a Devil Hunter hunting devils.