Lin Daiyu inherited the family business and ran the detective agency, and took over the murder case of a salt transport envoy from the south of the Yangtze River. She discovered that her father's sudden death was suspicious; she disguised herself as a man and went north to the capital, met Shen Yuxuan and jointly investigated the shadow organization; the shadow leader claimed to be her aunt and planned an incident at the Queen Mother's birthday party; Daiyu was framed and imprisoned, and after escaping from prison Uncover the mystery of her life experience; prevent an assassination at the birthday banquet, and her aunt dies of poison; find out that the imperial censor is behind the counter-revolutionary movement and bring him to justice; Daiyu puts aside her grudges and reforms the Detective Agency to train new people; marries Shen Yuxuan and compiles a record of strange cases; in the final chapter, she receives a letter of help from the border, implying that the exploration will never end
