Have you ever heard the sound of falling in love? "I love singing, but this is a secret to everyone." Ao Sakurai, a first-year high school student who is shy and always reads the air around her and acts. Her secret hobby. It's singing a song. Blue sings freely alone in an empty classroom. She thought that this kind of daily life would continue as usual ... without anyone noticing. The next day, Ao was preparing for a graduation ceremony <prom party> in the classroom with her friends. Suddenly, Shin Narita, the student council president and a popular second-year student at the school, came to the school. He is blonde and handsome, and Shin is the exact opposite in appearance and content.