It's been a few months since Kohane moved into her new apartment in Tokyo. Sometimes to unwind, she decided to sing at night on the balcony. She rarely did it in the morning because she was too shy, after all no one would hear her...

Well, that's not right, though. Her neighbor, Toya, ever since Kohane moved in, secretly always heard her singing. Sometimes, he would even sit by the balcony of his own apartment room and listen to Kohane sing. Or if he had time, he would sometimes play his violin to accompany Kohane if he knew the song she was singing, putting aside the fact that he didn't like classical music. Miraculously, Kohane didn't notice the sound of his violin playing.

Until one day, Kohane was, as usual, singing on the balcony quietly. She paused for a moment to reflect. Her ears accidentally heard a slight noise from her neighbor's room, so Kohane decided to take a little peek at the balcony next door. Her eyes widened when she saw her neighbor, Toya, flipping through a tone book with a serious look before testing the sound of his violin. Wasn't that the song she had just sung?