In a small town, there is a bookstore called Tingyu. The bookstore is not big and inconspicuous, but this store is not simple either. There were only two people in the store, the store owner, and his assistant. The boss looks to be about thirty years old. He often sits on a chair in the store, drinking tea and reading a book. But his assistant is a young woman about twenty years old. On weekdays, they just burn incense, make tea, read and write in the bookstore, but no one knows that the two of them are also doing transactions of equal value.