Jae-in (Ha Seok-jin) is the grandson of Lee Gwi-cheol, chairman of the Sung Hyun Group. He lost his father at a young age and grew up under the strict teachings of his grandfather. The grandfather and grandson, who have very different personalities, have disagreements on many things. As time goes by, the contradictions slowly accumulate and eventually break out. After a big fight with his grandfather, Jae-in left home and began to live alone. One day, Jae-in accidentally learned that his grandfather had made a will, and if Jae-in could not marry a woman named Da-hyun (Jeon So-min), he would lose the right to inherit all the inheritance. The angry Jae-in regarded Da-hyun as a liar who deceived and confused his grandfather, and many conflicts arose between the two. However, as time went by, Jae-in gradually discovered the kind and gentle side of Da-hyun. Jae-in, who had always played the role of a dandy, felt a strong throbbing deep in his heart.