Prince Oh Sehun lives a peaceful life in his Kingdom, blissfully unaware of any dangers outside of his castle walls. Life is perfect for the prince. That is until once day, a dangerous war breaks out. With their kingdom in danger to be completely destroyed, they have no choice but to marry their son to an opposing kingdom to strengthen their forces. Sehun is forced to marry Prince Kim Jongin, a notoriously cold-hearted man. Miserable with this arrangement, Sehun finds that the only tranquilit