For years, the Tokugawa Shogunate has prospered in peace and now the Shogun Tokugawa Ieyasu is finally finding the years of death coming closer to him. Listening to the voice of his adviser, he summons the heads of the Kouga and Iga Ninja clans to him.

For four centuries, the two clans have been at each other's throats, their common goal being to eradicate each other. Then the previous Hattori Hanzo had called for them to stop their feud and seal a pact to serve the Shogun for the peace of the country, which the clans reluctantly agreed to. Things are however about to change...

Each clan is to be the Champion to each of his two grandsons. The pact has been revoked! Ten selected ninja champions of a clan must be killed for the other to claim victory. The patron of the victorius clan is hence proclaimed to be the successor to the position of the Shogun.

The battle unfolds in intrigue befitting these ninjas of intrigue. Ninpous fly as their mysterious powers are unleashed in the gathering storm.

In the center of this storm, stands Gennosuke of the Kouga and Oboro from the Iga, the two heirs of the clans who are deeply in love and possessors of powers deadly to the ninjas. What will happen to them when they learn of the revocation of the pact?

Ten ninjas of a clan must fall!!! However who shall fall along with them?