It is the end of the Edo period, the final years of the age when a man would live and fight as a samurai, entrusting his life and beliefs to a sword. The long peaceful era of the Tokugawa Dynasty begins to be overshadowed by the arrival of Westerners. During the upheaval, when youths seek to prove themselves in a new age, a nefarious existence called Hasha no Kubi, or the Head of the Conqueror, is about to bring turmoil and chaos. It is said that the person who obtains the head that awakens in revolutionary times, will rule over the whole country. In the midst of this all, there is another shadow existence called the Eternal Assassin, destined to fight Hasha no Kubi in order to seal it away. Both have been fighting each other since time immortal, and their conflict has affected the history involving those wanting the power. One of the seekers wants the power for their own purposes, another to exact revenge, and a third to fulfil ideals... but who will gain the Hasha no Kubi?