A hero who defeated an evil demon king—his descendant, Harold. In this peaceful era, Harold has become a convenient handyman for the townsfolk.

One day, a sacred book predicting the world's destruction is discovered. The condition to avert this catastrophe is... "You must complete the 'Shinkon Quest' with the demon king's daughter." Thus begins Harold's unexpected married life with Yona, the demon king's daughter. While Harold feels bewildered, Yona expertly handles household chores and sweetly pampers him when he's tired. However, she harbors a secret...