On her wedding day, Su Qingyu, a daughter of a tea shop in Jiangnan, saw blood dripping from the bottom of her wedding sedan, which triggered her to explore the life experience of her mother, Ye. She discovered that her mother's dowry box contained sulfur, saltpeter and other substances used to make strong gunpowder. From a book of Su Dongpo's poems, she used the ink dot code and the secret map of the courtyard to deduce that her mother might have left clues in the abandoned hut in the old bamboo forest south of the city.
