Dankichi, a Japanese boy, was washed away while sleeping on a fishing boat with the rat Lord Kari, and washed ashore on an island in the far south. There, he is captured by the barbarian princes (indigenous people of the island) that he meets, but thanks to Prince Cali's quick wits, he ends up being respected as a king by the barbarian princes. Together with them, Dankichi will build a civilization based on his wisdom.