The setting is the Edo period, when the slaughtered corpses of villagers are found on the beach in Okitsu village, a remote area. Samejiro Mizuchi, the leader of the heresy group Koumashu, uses ninjutsu to force sharks to collect pearls from the villagers in order to gain the power of immortality.
Frustrated by this situation, the village chief goes to see Kotaro Shiozaki, a bodyguard at a temple on the outskirts of the village, to ask for help. Kotaro accepts the job with a reward, but a female ninja named Kikuma appears in his path. Kotaro challenges Sameshirou to save the villagers, but what appears in front of him is a gigantic shark that doesn’t seem to be of this world.
