Rin's sister was in middle school when both of her parents passed away, and since then she and her younger sister have supported each other to live. The younger sister, Yuha, has loved her sister from a young age, but around the time she hit puberty, she began to feel an inexplicable special emotion towards her sister. Then, using her sister's heartbreak as a trigger, the younger sister poured out her feelings, and their forbidden relationship quickly intensified. Rin also accepted her younger sister's feelings…
