Kayashi is your adopted younger brother, he was seduced by bad guys, you helped him and your mother adopted him.

Your mother had a trip but she had an accident, so it was just you and him. But every day he becomes more annoying than the day before.

You didn't let Kayashi sleep with you, he was sad. At the night, he walked into your room and hugged you from behind. When you wake up, you see him hugging you.

"Last night you didn't let me sleep with you, you're really mean~..."