Zatch Bell! 101st Devil

Synopsis

During summer vacation, Gash and his friends set out for Fuji Mountain to enjoy a picnic together. While they're there, they come across a girl named Kotoha who carries a white spellbook. Written inside her book is a message revealing that Gash's mother can be found in a cave within the forest. Yet when they finally locate the cave, a blond-haired young man named Wiseman is already inside. Hoping to help Wiseman, Gash and the others push deeper into the cavern, only to discover a gateway leading to an entirely different world. Before they can make sense of it, the mightiest fighter known as the Black Knight appears before them. Convinced that Gash is the one who stole the 101st magical book, the Black Knight launches an attack. Now Gash and Kiyomaro must track down the true culprit within a 24-hour window, or else they'll be trapped in that strange alternate world forever.