Kim and Rain are the siblings of the real estate Kannakool family. Rain is a 4th year student who is friendly and very different from his younger brother, Kim, a 3rd year student who is quiet and introverted. The two siblings have a friend and bodyguard named Phayu, the son of the Kannakool family's butler. The world of Kim changes after he meets Sun, who just transferred to the university. Sun is an optimistic person that loves playing the guitar but was born with heart disease. A good relationship forms between Kim and Sun in the classical music club, but misunderstandings, rivalries, and family problems await them in the near future. What destiny will they face?