In 2023, Eun Gyeol (Ryeoun) is a high schooler with a passion for music. During the day, he is a studious model pupil…but at night, he rocks out as a guitarist in a band. But when he stumbles across a strange yet alluring music store, he goes hurtling back in time to 1995. Here, he comes face to face with his father Ha Yi Chan (Choi Hyun Wook) – as a high schooler!