The flashback to the Heian period continues. Tsuna Watanabe leads his clan and his Kugai into battle against the Imperial forces as the two young kais realize they are the tools of those around them. The evil regent Einyo manipulates Tsuna into unleashing the full power of the Kugai. The willpower of Yushiro and Miharu bring an end to the impending terror, which leads to the defeat Einyo and the death of Tsuna. The new leaders of the Watanabe clan agree to bury the secrets of the Kugai and retreat back into the mists of time. In the present, Yushiro and Miharu gain a greater understanding of their place in the continuing legacy of the kai.
朝廷に反旗を翻す綱が渡辺党の実権を握り、憂四郎と美晴も渡辺党の一員として戦わざるを得なくなる。二人が振るう骨嵬の力に多くの兵士が殺され、戦場となった鳥部野に屍が満ちる。あまりの惨状に二人が耐えかね、骨嵬が動きを止めたそのとき、鳥部野の地に異変が発生する。