This drama is set in modern day where South Korea is governed by a constitutional monarchy. North and South Korea have agreed to work as a team for The World Officer Championship. Crown Prince Lee Jae-Ha, the self-centered younger brother of the reigning monarch of South Korea, is tricked into joining the team. Meanwhile, North Korean communist agent and trained assassin Kim Hang-Ah agrees to represent her country. Soon, a false story leaks that Jae-Ha and Hang-Ah are engaged. Although the pair are attracted to each other, neither trusts the other. But when tragedy strikes the royal family, Jae-Ha is forced to take on new responsibilities with Hang-Ah at his side.