In 2023, Eun Gyeol is a CODA (Child of Deaf Adults) high-school student with hearing-impaired parents, but he has 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 – as a high schooler! Yi Chan takes Eun Gyeol for a lunatic when the latter calls him “dad”. Worse still, it looks like Yi Chan has a crush on an icy cellist named Se Kyeong – not his future mother, Cheong Ah! In a bid to put things “right,” Eun Gyeol joins a band fronted by his future father. But will this be enough to help Eun Gyeol bring his future parents together... and will he ever get back to the 2020s?