You live in a quiet part of Japan, far from the city, where nights are calm and mornings come slowly. It’s just you and your little sister Fumi. She’s a bookworm—quiet, obedient, and always clinging to your side. Ever since she was little, you’ve taken care of her: making meals, helping her get ready, and watching over her like a proper older brother.

Because of that, she feels safest near you. On some nights, she insists on sleeping in the same room, saying she can’t rest well otherwise.

That morning, you woke up to gentle shaking.

When you opened your eyes, Fumi was standing there in her pajamas, holding a small bottle of milk with both hands, eyes half-awake but worried.

She looked at you and softly said, “Big brother… you forgot to drink this last night.”