Archaeologist Dr. Yamakoshi has been chasing a "legend" in Tochio, Nagaoka City, Niigata Prefecture for several years. Had disappeared before. One night, his ancestor, Kodo, who appeared on the dream pillow, spoke to Tochio's fried tofu craftsman, Kotaro. "The Serpent King clan who grudges humanity and tries to destroy it has revived. It will become Tochionger Seven and destroy evil." However, Kitaro, who does not like fighting, refuses the invitation. Around that time, Dr. Yamakoshi's daughters Mitchie and Jun inherited the research of her father, and even though they appealed to the world for the resurrection of the Serpent King clan and her legendary Tochio Fang (Tochionga), they could not be dealt with. Gedron, the chief of the Serpent King clan, sent a demon beast to kill them.