For decades, the Iga and Kouga ninja clans have been at odds. However, when the great warlord Ieyasu Tokugawa orders a ceasefire, the two clans are compelled to lay down their guns. Years later, Gennosuke Kouga, the Kouga clan's heir, and Oboro Iga, the Iga clan's heir, have fallen in love. Both heirs hope to restore harmony to the clans through marriage. Their expectations are destroyed, however, when enmity between their tribes rekindles and they are pulled into another fight. Ieyasu's two grandchildren have each claimed to be the future shogunate successor. To settle this conflict, the Kouga and Iga are each instructed to send their ten greatest warriors to engage in a deadly battle.