For the sake of parents' business plans, Hidaka Sana moved to Tokyo. Five years later, he has become a high school student, and returned to his hometown, Sakuranomori. He feels uneasy because the streets of his hometown and his old friend he meets again have changed a lot since five years ago. The most changed thing is his childhood friend, Yatsushiro Nanaka. She used to smile sweetly with innocent eyes, but now she has withdrawn herself and is gloomy.