In the late 1960s, 'C'est Si Bon' is the music bar where every acoustic band's dream lies, and Korea's leading folksongs were born. It is where Geun-tae, the naive country boy met the young musical prodigies Hyung-joo and Chang-sik, and formed the band named after - the C'est Si Bon Trio. As the three young artists bicker over their music, beautiful socialite Ja-young enters the picture and becomes their muse, and a series of moving love songs comes from it. Geun-tae's pure-heartedness wins Ja-young over but when she accepts a once-in-lifetime opportunity for a shot at an acting career, they part ways. After 20 years, the untold story of their love, song, and youth at 'C'est Si Bon' is finally brought to light.