Focused solely on little sisters, Itsuki Hashima is a light novelist who has a peculiar obsession. Despite his strange tendencies, he is surrounded by an intimate group of friends, including Nayuta Kani, a brilliant writer with a perverted nature who has feelings for him; Haruto Fuwa, another accomplished author; Miyako Shirakawa, a close friend from college; and Chihiro, his step-brother who manages the housekeeping and cooking. Together, they engage in eccentric activities, embark on unplanned adventures, exchange witty banter, and cheer each other on. Nevertheless, everyone must confront their personal dilemmas, whether it's grappling with deadlines or confronting painful experiences from their past.