This feature length family oriented anime tells the story of a kappa - a mischievous Japanese river spirit - who is orphaned during the Edo period when his father is killed by a samurai. He comes to life again 200 years later when a small boy discovers the fossil he's been sleeping in. The boy takes the kappa home, where he is adopted into the child's family, but the water imp finds that the modern world is a difficult place, and the riverbeds and bogs where he once made his home have been replaced by streets and buildings. Soon, however, the kappa learns about the value of a loving family, and the family learns about the importance of preserving the natural environment.