"Is it okay to call you Big Brother?" One day my father remarried. The person who appeared before me as my "little sister" was... what a surprise! It was an anime cosplay AV actress who I always used as masturbation material! Her name was "Aoi". At first I thought it was just my imagination, but as I peeked at her, I became convinced that it was the same person! If I tell "Aoi" about this, she will surely be in trouble and do what I want! Maybe I can do something naughty with the girl who I always jerk off to! I was excited and approached the core of the matter, but for some reason, things took an unexpected turn... An erotic life where I am at the mercy of my AV actress "little sister"!