Two unemployed samurai are saved from drowning by the Ainus, a primitive people on a northern Japanese island, and are torn in their loyalties when the possibility of war arises between the Ainus and a band of Japanese settlers.
Shipwrecked and then rescued by Ainu, a strange, round-eyed people, samurais Zenta and Matsuzo soon find themselves captives of these strange people, and their escape only leads them into a mystery involving bear attacks on a nearby Japanese settlement.