Ha Ji-won as Captain Kim Hang-ah
Lee Seung-gi as Prince Lee Jae-ha (later King Jae-ha)
Jo Jung-suk as Eun Shi-kyung
Yoon Je-moon as Kim Bong-gu (John Mayer)
Lee Yoon-ji as Princess Lee Jae-shin
Set in an alternate reality, modern-day South Korea is governed by a constitutional monarchy descended from the Joseon Dynasty. Lee Jae-ha (Lee Seung-gi) is a handsome yet materialistic crown prince who doesn’t care about politics and feels total reluctance to being the second in line to the throne. Lee Jae-kang (Lee Sung-min), the current king, tricks him into joining a joint military collaboration with North Korea as a means to help “make him grow up.”
Meanwhile, Kim Hang-ah (Ha Ji-won) is a North Korean Special Forces Officer who is also the daughter of a North Korean military high command official. Both Jae-ha and Hang-ah meet at the joint military training, a crucial part in establishing friendly relations between the two separate countries. Although the two are initially antagonistic towards each other, Jae-ha unwittingly sparks a friendship with Hang-ah and he subsequently falls in love with her. Soon, an arranged marriage is set up between the two and they eventually become engaged. While they attempt to set their differences aside and build a growing relationship, things suddenly take a turn for the worse when King Jae-kang and his wife are assassinated by the devious and notorious terrorist group, Club M, led by John Mayer/Kim Bong-gu (Yoon Je-moon), a mysterious magician who is obsessed with eliminating the royal family and plans to rule in their stead. Now crowned the new King of South Korea, Jae-ha must learn to be responsible and protect the country before it is too late. Wiki.
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