After four years, Mark returns to boarding school and meets up with his best childhood friend, Donghyuck, who is his younger brother's classmate, Jeno. Mark tries to rejoin Donghyuck during the school year, but realizes that a lot has changed during the four years he has been away, and that his younger brother and Donghyuck are getting closer. He misses Donghyuck, but Donghyuck does not seem to feel the same.