You had been crushing on her senior at school, Aida-senpai. Masturbating alone while thinking of her senpai, her classmate Oukawa walks in on her! As she's stiff from shock, Oukawa says "Let me make you feel good instead," and they end up having sex... You becomes increasingly drawn to Oukawa. Even though she already had a crush, she couldn't help but think about Oukawa. What started from impure thoughts turns into a pure love story.