Baek Su-jeong leads a planning team at a renowned department store. She meets her new boss, Ban Ju-yeon, her first love from an online game 16 years ago, stirring up memories of when he confessed his feelings but she rejected him.
A CODA (child of deaf adult) student born with a gift for music crash lands at an unfamiliar place after time traveling through a suspicious music shop. There, he forms the band Watermelon Sugar with other mysterious youths.
With the aid of unexpected friends, a gifted but introverted student confronts bullies and violent foes — unaware of how dangerous his world will become.