Haechi

The Crown Prince is Arrested (1x21)

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Saheonbu and Hanseongbu together, put their hands on the investigation of the master murdering case. Saheonbu arrests the Crown Prince for hiding the child who killed Jipyeong Oh, but is really trying to cover the human trafficking. Mun Su and Yeo Ji are all worried for the Crown Prince and so is His Majesty.