The battle to determine who will be the next king of the mamodo world takes place every 1,000 years in the human world. 100 mamodo each own a spell book that allows them to draw out their unique powers, and they must team up with a human in order to fight for their own survival. Zatch Bell, a happy-go-lucky but fiercely determined child, is one of 100 mamodo chosen to fight in this battle. His partner is Kiyo Takamine, an aloof junior high prodigy who could learn a thing or two from Zatch and his optimistic approach to life. The bond between Zatch and Kiyo deepens as they continue to survive through many harsh battles in Zatch's pursuit to become a "kind king."