A student tries to fix a problem he accidentally caused in OZ, a digital world, while pretending to be the fiancé of his friend at her grandmother's 90th birthday.
A small, lone Kappa miraculously survives over 200 years into modern day Japan, when he is found by young Koichi. Coo, who is secretly adopted by Koichi's family, searches with his new human friend for unpopulated places in hopes of finding any remaining of his kind.
