Su Yuan, an ordinary young man, accidentally discovers that an ancient writing brush can transport him between the modern world and Xianyang during the Warring States period. There, he meets the young Crown Prince Fusu. Traveling frequently between the two worlds, he brings modern agricultural, architectural, educational and cultural technologies, along with various new discoveries, to Ying Zheng. The King of Qin and his ministers also make repeated visits to the modern world to learn, recruit talented people ahead of time and avert historical crises before they occur. Two generations of Fusu meet across time and space, and everyone works together to build the Qin state, forging a new path toward stability and prosperity.