Living alone as a timid high schooler, Ooyama's solitary routine gets disrupted by the spontaneous intrusion of Riko Akutsu, a delinquent classmate. Claiming his room as her own hangout space, she indulges in his manga, treats, and even his bed for daily naps. Despite Ooyama's exasperation and futile attempts to oust her, her persistent presence evolves from annoyance to a peculiar bond, sparking unexpected changes in their dynamic over time.