During the reign of King Sejong in the 15th century, the Joseon Dynasty was the embodiment of the perfect state. To the Ming China, the aspiring imperial power, Joseon presented an obstacle to territorial expansion. To protect themselves from war, King Sejong develops a secret weapon to defend their territory and take back their land and supremacy.

Jung Jae-young
as Seol-joo

Han Da-gam
as Hong-ri

Huh Joon-ho
as Chang-gang

Ahn Sung-ki
as King Se-jong

Shin Jung-keun
as Pan-soo

In Gyo-jin
as In-ha

Lee Do-gyeong
as Hong-man

Cho Won-hee
as Yu-bong

Jeong Seong-mo
as Sa Ma-seon

Kim Myung-soo
as Kkya Oh-ryung