(from ebookjapan):

Due to a major earthquake that hit the Tokai region, Mt. Fuji was surrounded by a large fault line and turned into an isolated island on land. Unfortunately, Mr. and Mrs. Ida, who were visiting an animal park at the foot of Mt. Fuji, lost their beloved child...

Ten years have passed since then. Kyosuke Ida, who was raised by wolves and grew up to be a kind-hearted boy who can speak human language, sets out on a journey in search of his parents!