Eun-gyeol gets stuck in 1995 and doesn't know how to return to the present. What's worse is that he meets his young father, Yi-chan, who can talk and wants to start a band to impress a girl who isn't Eun-gyeol's mother. Eun-gyeol poses as Yoon Dong-jin, a musical genius, in order to try to become a member of Yi-chan's band.