The older sister, Kozue, and the younger Hina, Hina, lost their parents at a young age and have lived together, supporting each other. Hina has always loved her kind and caring older sister and has always been very attached to her, but as she grows up, she gradually realizes that her love interests are women. The older sister also had a terrible heartbreak, and was tired of men, but was interested in women, but didn't have the courage to take the first step.