In the fourth year of Emperor Gaozong's reign in the Tang Dynasty, Chang'an City was shrouded in the mist of early winter, and the afterglow of dusk shone on the red walls and green tiles, adding a bit of mystery to this imperial city. The vendors on both sides of the official road had closed their stalls, and only the lanterns of the restaurants were hung high, illuminating the passers-by. A man in a green shirt was walking slowly on the street. He looked ordinary, but his steps were measured and every step exuded confidence and calmness.
