Princess Eun-myeong meets Seo-yul, whom she gave for no purpose, by chance and falls in love. In order to get his attention, she goes to Boryeong to meet him with the pretext of taking blood. But for some reason, Seo-yul only pushes Eun-myung away from him, and Eun-myung is frustrated with Seo-yul. But she doesn't give up and she expresses her feelings towards him... 'When no one believed me, only you gave it for me.' 'Be my patron.' 'I will guarantee you wealth and glory.' Princess Eunmyeong, the most straight girl in Joseon! Will she be able to win the heart of Seo-yul, the best iron man in Joseon?