Chaewon is the Crown Princess of Xiwang, the Captain of the Army and the most skilled swordswoman of the entire realm. She does not need a bodyguard. 

But after Chaewon is attacked in her private chambers and the King forces her to work with a certain very disagreeable bodyguard, she will have to fight battles she'd never imagine herself involved in.

♚♚♚

“Thank you,” the King said, then turning to Chaewon. “The Captain of the Guard appointed this woman as the most skilled guard apart from himself. My daughter, she goes by the name of Son Hyejoo. I have just personally observed this woman in combat and judge that her skillset is different than yours, and therefore, will largely complement your weaknesses in combat. I place my trust on the both of you to cooperate in a way that will make you a near invincible pair, in the best interest to keep the princess and therefore the lineage of this Kingdom in safety.”