Modern firefighter Lin Henghun traveled to Tianbao Chang'an and became a low-level delinquent in Wuhoupu. Starting from fire-fighting innovation, he improved equipment, established new systems, and helped the government investigate cases. However, he offended the conservative forces of the clan and was framed repeatedly. He joined forces with Li Ruxun, a descendant of a down-and-out noble in Longxi, to strengthen his strength in the cracks and expand the city's defense infrastructure. He also fell in love at first sight with Li Ruxun's sister, known as the female Hua Tuo, Li Rumin. Facing the approaching Anshi Rebellion, he used modern knowledge to fight against the old order and the catastrophe of troubled times, and single-handedly saved the fate of the Tang Dynasty.
