HBAD-262 My younger sister is acting a little strange... Airi Sato is being trained by her new older brother.

My mother remarried. - I just couldn't like my new father and brother. - My older sisters look at my older brother with curiosity, and my mom keeps flirting with my dad. - One day when I came home from school, my sisters were having sex with my brother. - My brother caught me staring at me and forced me to do it. - That's when my older brother started training him, involving his family.