Dokuganryū, a legendary samurai from the ancient imperial capital, was stripped of his lands and had his entire family slain by the emperor’s decree.

Vowing vengeance until his last breath, Dokuganryū set out to destroy his enemies. However, the emperor, aware of Dokuganryū’s plans, assembled a group of highly trained ninja assassins to eliminate him.

Thus begins a long and bloody battle set in the Edo period.