A king and his archivist search for the truth behind a crime that threatens the stability of the kingdom. Lee Sun-kyun as King Yejong
Kang Chan-hee as young King Yejong
Ahn Jae-hong as Yoon Yi-seo
Kim Hee-won as Nam Gun-hee
Kyung Soo-jin as Sun-hwa
Jung Hae-in as Heuk-woon
Joo Jin-mo as Jik Je-hak
Jang Young-nam as Soo-bin
Park Hyung-soo as Officer 1
Jo Young-jin as Second vice-premier
Kim Hong-pa as Joseon dynasty prime minister
Kim Eung-soo as First vice-premier
Kim Tae-hoon as Royal court physician
Kim Jung-young as Manufacturing court lady
Choi Ri-ho as Fisherman Gi-soo
Park Jung-min as Crown Prince Ui-kyung (special appearance)
Sung Byung-sook as Daebi (special appearance)
