Fourteen-year-old Kiyo, an arrogant genius who is teased mercilessly at school, is given a strange boy, Zatch Bell, for his birthday to help him make friends, but Zatch turns out to have strange powers that change Kiyo's life forever.

In a world of animals where the strong eat the weak, Monoko the tanuki stumbles across a strange creature the likes of which has never been seen before-- a human baby! While the newborn has no claws or teeth to protect itself, it does have the rare ability to speak to and understand all the different animals. Can Monoko and the baby team up to protect the tanuki pack from vicious wildcats?