Little mountain spirit accidentally lost his way, accidentally came to the lake, but saw an old mountain spirit sitting at the end of the trestle. In the process of talking with the old mountain spirit, the little mountain spirit accepted a very important task: "ride" the dream fish for the old mountain spirit to find his lost daughter for 50 years! What kind of experience will he have on earth? He can help the old mountain spirit to achieve the long-held wish of fifty years?