We begin in 1865, when the Shogunate is on its last legs, but still capable of punishing its enemies. One is Izo (Kazuya Nakayama), an assassin in the service of Hanpeida (Ryosuke Miki), a Tosa lord and Imperial supporter. After killing dozens of the Shogun's men, Izo is captured and crucified. 

Instead of being extinguished, his rage propels him through the space-time continum to present-day Tokyo, where his finds himself one with the city's homeless. Here Izo transforms himself into a new, improved killing machine, his entire soul still enraged by his treatment in his past life. His response to the powers-that-be, whose predecessors put him to death, is the sword. 

His ability to leap through time, slashing as he goes, attracts the attention of the lords of the universe, who are like a pre-war House of Peers, in office for eternity. Izo, however, is not about to bow to anyone, even the lords of creation (he even rapes Mother Earth). 

In the final conflict, the prime minister (Beat Takeshi), calls in allies from all eras, from samurai swordsmen to the yakuza. It should be the most bloody and violent sword fight sequence ever staged.