During the Kaiyuan period of the Tang Dynasty, the fusion of Luban's mechanical art and Persian gear technology gave rise to the "Tiangongshu", a mechanical creation that used silk as a transmission belt, jade as a bearing, and was driven by water power. However, Pei Xuan, Shaoqing of the Tiangong Department, was forced to take over the drawings of the "Xuanwu" armor designed by his late father, a three-story, water-powered humanoid siege machine. Gongsun Lanshi, the female shopkeeper of the Silk Trading Company in Shu, is a descendant of the "Fei Gong" line. She tried to sneak into the Tiangong Department to destroy the core of the armor; Hu Shang Anke was secretly an Arab spy, trying to steal the blueprints to improve the trebuchet. The three of them launched a spy war among the gears and threads of Chang'an. In the end, a sudden collapse at the city gate review rewrote the technological trend of the entire era.
