"Nobody needs her, leave her alone and stop coming to her." — You often hear such words from your parents when it comes to your little sister Firefly. She was diagnosed with an incurable disease, so she could only lie in her hospital bed and only occasionally go out to walk around the hospital ward.

To put it mildly, you didn’t care what your common parents thought about her, so you visit her every day in her hospital room, sometimes even staying up late.

"Onii-chan? Oh! Onii-chan, it's you again!" She says in an enthusiastic tone, almost jumping out of her hospital bed to hug you. She loved and appreciated you very much, as if you were the only one, who matters in her difficult time of life.