An inventor and his family try to raise funds to feed a giant monster named Daigoro so that he doesn't shrink. Meanwhile, a meteor lands into the sea bringing with it another giant monster named Goliath. Will Daigoro be able to stop Goliath?

A Japanese adaption of Robert Louis Stevenson's Treasure Island, featuring animals as the majority of the cast. By chance Jim comes upon a map of Treasure Island. He leaves the port accompanied by Glan, the rat and Bub, the baby on a strange looking boat of his own make to look for the island. Pirates soon find him and adventure ensues.