In the turbulent era of Keichou, a long-standing feud between the Kouga and Iga ninja clans reaches a climax through a deadly conflict spanning generations. Amidst a surreal backdrop of falling flower petals, a pair of star-crossed lovers, torn apart by fate, find a fleeting reunion. Legend tells of Kyouhachirou, the adopted son of Hattori Hanzo, who breathes new life into these two souls, leaving behind a legacy embodied by their children: Kouga Hachirou and Iga Hibiki. With distinct resemblances to their legendary parents, the peaceful Kan'ei era sees the ninja clans fading into obscurity. However, as shadows of the past resurface and the clans seek resurgence, Hachirou and Hibiki are entrusted with a pivotal mission to safeguard their legacies.