Sang-hoon, now an established composer, is pulled back into the memories of his youth when a familiar melody reminds him of a long-buried past. The story shifts to 1980s Seoul, where the young Sang-hoon, his protégé Hyun-woo, and a singer named Yeo-ju meet inside the live café “Blue Azit,” bound first by music and then by growing affection. Both men fall for Yeo-ju, but their musical ideals collide with the reality of student protests, censorship, and the commercial pressures of the era. A song completed with Sang-hoon’s guidance spreads through the protest movement, turning Hyun-woo into an unintended symbol of resistance — and eventually leading to his arrest. While Hyun-woo disappears from sight, Sang-hoon and Yeo-ju slowly grow closer, only for Hyun-woo to return years later and reopen wounds neither of them has fully faced. Blending romance, memory, and the longing of songs that outlive their singers, the musical paints a portrait of love and artistic youth forever tied to the streets of Gwanghwamun.