Before the incident, Mahiro Oyama was an ordinary guy who enjoyed playing erotic games. However, upon waking up one morning, he discovered that he had transformed into a woman. The reason behind the odd transformation was due to his younger sibling, Mihari, an eccentric scientist who used Mahiro for her latest experiment. Mahiro dislikes living as a woman, but Mihari is determined to observe and study her brother's changes. Mahiro's life will no longer be ordinary, and things are expected to get even stranger.