I'm a ronin student from the countryside living in a dormitory in Tokyo, secretly cohabiting with Nanaho, the daughter of the dorm matron who works as an office lady. Though older than me, she's adorable and popular among the residents. By chance, she started taking care of me and tutoring me in my studies, but it didn't stop there... Nanaho's lips were so soft—my heart trembled the moment she kissed me. Inappropriately aroused, I ended up climaxing inside her mouth. One night, drunk and unsteady, Nanaho burst into my room and aggressively came onto me again. Once more, I came inside her mouth. Wanting to clarify this ambiguous relationship, I resolved to confess my feelings when she brought me a late-night snack. What will become of my "first time"?