In the winter of 1972, heavy snow closed off the Greater Khingan Mountains. Er Zhu, a forest farm youth, waited bitterly for ten years without seeing his missing father return, receiving only the passing of old forest ranger Zhou and a message concerning his father. Inside an old shack, a gripped old photograph left behind a warning: do not trust Uncle Liu. On the journey into the mountains to seek traces, children's footprints inexplicably appeared, strange occurrences in the forest happened one after another, abnormal sounds continuously came from the abandoned mine shaft, and footprints that had long disappeared resurfaced once again. A maze deliberately laid out by human hands covers up past events sealed away for ten years. Some people cannot let go of past obsessions, while others are trapped in greed. The snow-filled sky can hide tracks, but it cannot hide the secrets deep within human hearts.