While investigating the disappearance of a sick servant, Mao Mao discovers that Lifa's company lady, who is also her cousin, was plotting to hope to take her place! A gesture with very heavy consequences... Shortly afterwards, the emperor himself asks the young apothecary to accompany her to the temple of choice, in which one must solve a riddle and borrow the right passage in order to prove his status as heir to the Queen Mother. Alas, the sovereign fails to break the secret of the place... Will Mao Mao understand the message that lies in it?