Ooyama is a timid high school student who lives on his own, but it has not appeared that way lately. After forcing herself into his apartment on a whim, Riko Akutsu has claimed Ooyama's bedroom as her after-school hangout spot. The delinquent girl from his class enjoys taking naps in his bed, reading all of his manga, and consuming his snacks and drinks. To make matters worse, this is an everyday routine, leaving Ooyama to constantly deal with her antics.

Despite wishing Akutsu would go home, Ooyama's attempts to make her leave are futile, especially with his teenage mind falling prey to her arousing behavior. In due time, however, the mischievous teasing in their unusual relationship changes as the two grow comfortable in each other's presence.