Kirino Kousaka is the epitome of a model student with stunning beauty and exceptional grades. Balancing her academic life with a career in modeling alongside her friend Ayase Aragaki, who despises dishonesty and otaku culture, Kirino hides a deep secret. When her brother Kyousuke discovers her hidden stash of adult games, Kirino enlists his help while introducing him to the world of erotic games and anime. As Kyousuke delves deeper into Kirino's clandestine hobbies, he encounters new friends like the gothic lolita Ruri Gokou and the nerdy Saori Makishima, leading him down an unexpected path. Keeping Kirino's double life concealed becomes increasingly challenging as Kyousuke gets entangled in her world.