The protagonist, now living alone in the city, feels a deep emotional connection to his family back home. His reunion with his younger sister "Hikari," someone especially dear to him, awakens unfamiliar emotions within him. Hikari has grown—no longer a child, but a woman with a mature allure. As he becomes aware of her transformation, he unconsciously begins to see her as a woman, struggling with confusing feelings he cannot put into words. Their sibling bond starts to shift, quietly giving way to something deeper and more complex.