Chiharu lives in a 1LDK apartment with her daughter, Rai, after she died of illness from her beloved husband a few years ago. Chiharu never forgot his gratitude for her daughter, saying that she always smiled because she filled the hole in her husband's mourning heart. One day, he learned that Ki had a relationship with his neighbor, Nanahiro. Chiharu can't hide the joy that his daughter is at such a age. However, after this, an event occurred that changed the relationship between mother and daughter.