Secret: Untold Melody

Pianist Yoojun, who was studying abroad, comes to Korea as an exchange student for wrist treatment. On his first day at school, he is drawn by a mysterious piano melody and arrives at a practice room, where he encounters Jeongah. The two are irresistibly drawn to each other and grow closer as they spend time together. However, their meetings keep slipping through their fingers as Jeongah refuses to share her contact information. Meanwhile, Inhee, who believes Yoojun's gaze has always been on her, suddenly confesses her feelings, leaving Jeongah deeply hurt. After that fateful day, Jeongah disappears without a trace. As Yoojun desperately searches for her, he stumbles upon her hidden secret…