This work is generated by AI. Su Tang, a folk sachet artisan, spent painstaking effort finishing a begonia sachet custom-made by Madam Li of the embroidery workshop in the west of the city, with delivery agreed for the next day. However, the sachet was accidentally lost on the night before delivery. Valuing faith and integrity, Su Tang is frantic with anxiety; once she fails to deliver the goods, she will not only lose money but also ruin the reputation she has painstakingly built. Gu Yan, a constable in the workshop area, happens to pass by. Relying not on arbitrary judgments or brute force, but on searching through minute street and alley traces like footprints and left-behind thread ends, he ultimately finds the sachet in a dilapidated mill.