A love story between a young man who has been forced to grow up too quickly, and a young woman with an ailment that has placed restrictions on her life. Natsuo has been looking after his younger brother and sister since the death of their parents. He has also been running the family bicycle shop. Yuki becomes the only person in the world in whom he can confide. For Yuki, Natsuo becomes the catalyst that has her trying to break out of her cocoon.
