The background of "Qin's Moon" is taken from the period from the unification of the six kingdoms by Qin Shihuang to the capture of Xianyang by Xiang Yu, the King of Western Chu. It has been translated into 7 languages and distributed to 37 countries and regions around the world. "The Great Wall" is the fourth part of "Qin's Moon". Since the collapse of the Mechanical City, the Mohist forces have been almost completely eliminated. The Qin Empire has returned to the dream of peace and prosperity. While the First Emperor in the Xianyang Palace used countless laborers to build the Great Wall, he was also carrying out a more sophisticated plan. Now this plan is almost complete, and the giant boat "Mirage" assisted by the Yin-Yang School has been built. Its magnificent and exquisite figure emerges on the other side of the sea level, like a fairy mountain on the sea in everyone's dream. In order to solve the mystery of the giant boat "Mirage", various forces gradually gathered in this peaceful seaside town. At this time, the protagonists of the story, Tianming and Shaoyu, were studying and living in the Confucian manor to avoid the pursuit of Qin soldiers. Then various strange events happened here, and the tranquility of the town was completely broken. Where is the giant ship "Mirage" going? Various forces are slowly gathering in Sanghai for this purpose. Various strange events are happening here, and the tranquility of the small town is completely broken. All the hatred of life and death, family and country, will condense at this moment...