Main •
Ryeoun as Ha Eun-gyeol : Eun-gyeol is the only hearing person (
CODA) in a family of deaf people. He is a model student by day, and a guitarist in the band at night. After having an argument with his father, where his father learned of his musical interest, Eun-gyeol time slips to 1995 and meets his parents when they were younger. He strives to know more about his parents' youths and shine their lives. •
Choi Hyun-wook as Ha Yi-chan •
Lee So-yeon as adult Choi Se-kyung :Choi Se-kyung is the cello goddess of Seowon Arts High School who was considered to be everyone's muse with her innocent beauty and elegant aura reminiscent of a scene in a movie. She was idolized by many boys either from her school or neighboring schools. Se-kyung is the daughter of the owner of Viva Music, a store that existed during Eun-gyeol's childhood. In the present, she has inherited the Viva Music store which has been redeveloped into a luxurious home. She keeps her father's handmade guitar, which she gives to Eun-gyeol as her father had wished. :On Eun-yoo: Se-kyung's daughter who looks exactly like her during her youth. Her mother dolls her up and forces her to become a cellist to follow in her footsteps. She lives in a disharmonious family until she is 18 years old, when her parents divorce. Upset with her mother's controlling behavior and her drinking habit, and after finding out that her father has remarried, she time slips to 1995 so that she can find her mother's first love, and cease her existence. •
Shin Eun-soo as Yoon Chung-ah •
Seo Young-hee as adult Yoon Chung-ah : As a child, Chung-ah was a cold and isolated girl who was born deaf. She dreams of a sparkling life like the great Mexican painter
Frida Kahlo. Chung-ah is aloof towards other people except to Choi Se-kyung, who is much friendlier toward her. In the present, she is the loving mother of Eun-gyeol and Eun-ho and owns a chicken restaurant.
Supporting Band members •
Ahn Do-gyu as Oh Ma-joo • Kim Hyeong-beom as adult Oh Ma-joo : Ma-joo is the band manager and Yi-chan's childhood friend. He is knowledgeable and resourceful. In 2023, Ma-joo owns MJ Entertainment who manages a famous rockstar Yoon Dong-jin. •
Yoon Jae-chan as Kang Hyun-yul : A drummer from the church band. He is very short tempered especially toward Yi-chan's antics. • Lee Soo-chan as Noh Se-bum : Se-bum is a talented keyboardist who majored in classical piano and studied abroad early.
Eun-gyeol's family •
Choi Won-young as Eun-gyeol's father •
Seo Young-hee as Eun-gyeol's mother Yi-chan's grandmother and the owner of boarding house. • Lee Seok-hyung as Jung Bal-san, a college student at a boarding house run by Yi-chan's grandmother.
People around Eun-gyeol •
Chun Ho-jin as Choi Hyun / Grandpa Viva : Choi Hyun is the owner of musical instrument store Baekya Music, later renamed as Viva Music. He was a famous rock star whose popularity decreased after his girlfriend became pregnant. His girlfriend is actually Choi Se-gyeong's real mother. He is supportive of aspiring musicians who seek his advice about music even later in life, when he tutors Eun-gyeol on the guitar. •
Jung Sang-hoon as master of the mysterious musical instrument store La Vida Music. Through the store, Eun-gyeol and Eun-yoo time travel to 1995. He keeps in touch with both time travelers through their dreams by calling them on phones, even broken ones. Cheong-ah's father who is the chairman of Jinseong Musical Instruments. As a businessman, he frequently travels so he has no idea how abusive Cheong-ah's step mother is. •
Kim Joo-ryoung as Lim Ji-mi, Cheong-ah's live-in tutor and later stepmother who serves as chairwoman of Seowon Arts High School Foundation. She uses harsh methods to torture Cheong-ah, who will be the next chairwoman of Jinseong Group. • Kwon Do-hyung as Yoon Joo-yeop, the main vocalist of Spine 9 who senses hears Eun-gyeol's musical talent and attempts to recruit him into his band. • Yeon Oh as Jeong Ji-oh, Spine 9 bassist. • Han Min as Bae Soo-tak, Chuncheon National University legendary guitarist. •
Kim Ye-ji as Mira Lee • Kim Mi-hwa as the Landlady
Special appearances • Kim Hae-jun as Choi Jeon, the DJ of a
tteokbokki restaurant. •
Park Han-sol as Eun-ho's girlfriend ==Production==