When I returned to my hometown after a long time, I heard that my stepsister from my parents' remarriage was apparently a hikikomori. Worried, I visited her. It seems Koiro was teased about having big breasts and that's why she became a hikikomori... I tried to comfort her, thinking I should do something brotherly, but her expression gradually changed… Since we're step siblings, it's fine right? And so, tempted by her huge tits, I ended up succumbing to her charm.
