Takuya Sakuragi has recently moved to Tokyo to go to college. Conveniently, his brother Takashi and his new wife live in the area, so Takuya moves in with them while he goes to school. In lieu of paying rent, Takuya begins to work at the family cake shop part-time.
One day, out of nowhere, a beautiful blond woman appears in the living room! Quickly, she reveals that her name is Silk, and she is a magical witch from another dimension who has become trapped here. And guess what? She needs Takuya's help to get her home! And how is this to be accomplished? With lots of female pheromones, apparently. Silk informs Takuya that she requires a large amount of female life energy to power the spell which will return her to her own dimension, so she orders Takuya to go out and seduce various women around him in order to gather this sexual energy.