甲賀、蜂屋、戸隠、風魔、雑賀の忍者たちは、力を合わせて蛙獣に勝利したものの、妖怪たちの恐るべき強さに遭遇し、伊賀の里を去ることを決意。妖怪退治の英雄であるヴァンジ、オエマ、オル、ロンザブロー、ジエンも、複雑な思いを抱きながらそれぞれの一族へと戻る。バートンは、倒した蛙獣が残した石像を調べ、ある仮説を立て始める。一方、近くの渓谷では新たな妖怪が誕生しようとしていた…。
Despite the victory against the frog beast through their combined efforts, the ninjas from the Koga, Hachiya, Togakushi, Fuma, and Saika clans decide to leave Iga Village after encountering the formidable strength of the Yokai. Even the heroes of the Yokai extermination, Vanji, Oema, Olu, Ronzaburo, and Jien, return to their respective clans, harboring complex feelings about the situation. As Burton investigates the stone statue left behind by the defeated frog beast, he begins to formulate a theory. Meanwhile, a new Yokai is about to be born in the nearby ravine…
