In the months since their last perilous quest, a fragile calm has settled over Edo. Daijiro dedicates his days to training the first pupil of his quiet riverside dojo, while his father Kohei a famed swordsman whose name still inspires awe drifts through an uneasy retirement, his razor-sharp mind too restless for leisure. But such peace never lasts long in the shogunate.

One chill autumn night, Kohei is set upon by a band of tsujigiri lawless street slashers who test their blades on the innocent. To his astonishment, the gangs leader proves to be no mere rogue, but in fact one of the most important officials in the land. What begins as a chance encounter soon blooms into a deadly game of pursuit, vengeance and, finally, siege, as father and son are dragged into the citys pitch-black heart.

Other adventures soon follow, including the task of bringing to justice their most evil adversary yet, a villain of monstrous proportions