In 2023, Eun Gyeol (Ryeon), a high school student and a CODA (Child of Deaf Adults), secretly pursues his love for music, balancing his days as a model student and nights as a guitarist in a band. However, his world is turned upside down when a mysterious music store sends him spiraling back to 1995. In this unexpected journey, Eun Gyeol encounters his father, Ha Yi Chan (Choi Hyun Wook), as a high schooler. Confused and thinking Eun Gyeol is delusional, Yi Chan dismisses his claims of being his future son. To make matters more complicated, Yi Chan is infatuated with a cellist named Se Kyeong (Seol In Ah), not Eun Gyeol’s future mother, Cheong Ah (Shin Eun Soo). Determined to set things right and reunite his parents, Eun Gyeol joins a band led by his young father. Will he manage to bring his future parents together and find his way back to the 2020s?