In the spring of 1934, while Gu Yunchen was writing the "Investigation Report on the Old Beiping City Towers", he came across "Classmate Shen" - Shen Jinglan, who was disguised as a man in the Drum Tower and was secretly tracing the brackets. He mistakenly thought that the other party was a naughty young man obsessed with old wood, and took him as a temporary assistant. The two climbed the stairs in the scorching sun and dust. Shen Jinglan refuted Gu Yunchen's Western-style doubts by memorizing the "Fashion of Construction", while Gu Yunchen discovered the small portrait of a lady hidden on the back of her drawing on a moonlit night. When he broke into her daughter's body by Jishuitan, a game about "who is deconstructing whom" quietly began. As the war cloud approached, when they worked together to snap up the data of ancient buildings, Gu Yunchen stuffed the only ticket southward into the sketch she drew of the flying fairy bird. Many years later, he received a handwritten copy of "Remnant Records of Peking" sent from Chongqing. The title page was inscribed: "You use a ruler to measure wood and stone, but I will use the rest of my life to measure your heart."
