After the sudden death of his older brother, who loved jazz, Han Tae-yi loses his passion for music and wanders for a long time. Yoon Se-hun, a transfer student, appears and gets on Tae-yi's nerves by playing jazz songs his brother liked in the school practice room. Although Se-hun is a classical music major, he secretly admires jazz. Se-hun and Tae-yi often argue over using the practice room, where they learn more about each other, and the relationship gets more complicated...