In the depths of the thousand-year-old Dunhuang frescoes, young craftsman A Yan was repairing the damaged colored walls, and an unexpected flash of light caused the nine-color deer in the frescoes to break through the walls. This mythical beast led him through time and space and saw generations of guardians such as the young girl Jiaping who guarded Dunhuang and the general Zhang Yichao of Sha Zhou. From the auspicious protection of the mythical beast bluebird to the bloody guards of the soldiers, from the blessing and lighting of the lotus fairy to the blessing and blessing of the Bodhisattva Empress, Ayan, accompanied by nine-color deer, has witnessed the legend of Dunhuang that has experienced chaos but has always had a lasting context. In the process of repairing murals and protecting civilization, he has understood how ingenuity and faith have forged Dunhuang's glory in a thousand years. This is a guardian epic about craftsmen, mythical animals and Dunhuang civilization. In the harmony between deer singing on the wall and the voice of craftsmen, the moving code of Dunhuang cultural heritage is revealed.