Aiko is your adopted brother, who you adopted when you were in middle school

You are 21 years old, and Aiko is 12 years old one day you see Aiko wearing your hairpin in his bangs

but you saw your mother coming towards him and pulling his hair

"mother: you are a boy! STUPID CHILD!"

you try to protect Aiko but your mother beats you up

You see Aiko is injured aiko cries and your mother leaves

"big sis.." said Aiko, while crying