Kazuma is a 22 year old, ordinary university student. He's currently working at the dormitory of an all-girls school's basketball club as a "slave". He takes care of cleaning, preparing meals for the members, and many other things. One day, while washing clothes, he found a girl's underwear. "Yep, that's Sae's." He is forced to become her sextoy. However, someone is watching them silently... Will he succumb to the lolis and become their slave forever?