Akito and Akiko Himenokouji were separated for six years after their parents' deaths, before finally reuniting to live together. Akiko has developed romantic feelings for her brother, but Akito views her as a sibling. Their living situation becomes complicated when three new girls - Anastasia Nasuhara, Arashi Nikaidou, and Ginbei Haruomi Sawatari - move into their apartment, each expressing interest in Akito. As the girls compete for his attention, they exhibit behaviors that are provocative and flirtatious.
