In the third year of the Zhonghe reign of Emperor Xizong of the Tang Dynasty, in the third autumn after the fall of Chang'an, the sycamore leaves in Tongtuo Lane were once again covered with bluestone slabs. Shen Zhiwei, who was once a child of an aristocratic family, disguised himself as a painter and sneaked into the mansion of the rebel general Zhu Wen in order to find his abducted sister Shen Zhiyi. However, he was accidentally involved in a secret related to the lifeline of the Tang Dynasty - his sister's disappearance was not accidental. She had hidden in her body the fragments of the "Mountains and Rivers Sheji Map" handed down from the Taizong period, and this scroll is the key to the struggle between the rebels and the vassal town.
In the shocking mansion, Shen Zhiwei dealt with the thoughtful Zhu Wen, while establishing contact with the maid Su Wan who concealed his identity, and the nostalgic general Yang Fuguang. He discovered that the "Mountain and River Sheji Map" not only marked the defenses around Chang'an, but also concealed the location of the royal family's secret cache of grain and weapons, and even revealed the truth about the "Secret Case of Bronze Camel Lane" during the Wu Zetian period. As the fragments gradually gathered together, Shen Zhiwei realized that this battle had long gone beyond power and land, and behind it was the ultimate battle to protect the bloodline of the Tang Dynasty and overthrow the dynasty.
When the rebels are about to hunt down the fleeing royal family of Xizong, and when the iron cavalry of the feudal town approaches Chang'an, Shen Zhiwei must make a choice between family ties and home country - whether to take his sister to escape from the troubled times, or to use the secret of the "Mountains and Rivers Sheji Map" to risk everything and save the last hope of rejuvenation for the Tang Dynasty. The autumn wind of Tongtuo Lane blows, but what cannot be blown away is the character of the ancient Tang Dynasty, and the morality and responsibility of an ordinary scholar in troubled times.
