Lu Yuexi may look charming and delicate, but she is actually a formidable fighter. As a professional bodyguard, her unusual constitution often makes her employers develop feelings for her. After being hired by Yan Yiyu, the heir to a wealthy family in Yuncheng, she can only hope he will keep a clear head. Yan Yiyu appears gentle and refined but is cold inside. A firm believer in science, he scoffs at the idea of her so-called special constitution and is convinced he will never fall for her. As they spend their days together, the two become entangled in a battle between reason and emotion.