With only one more year of fun school life left, the teacher I've always admired, Terabayashi-sensei, has finally become my homeroom teacher. The most popular teacher in the school, she's kind, beautiful, and my ideal teacher. However, for some reason, my grades have recently dropped. It's because the teacher's chest is so exposed that I can't concentrate on my studies at all. Even seeing her bra makes my heart race, but I can't believe I can see her nipples... And so, the teacher, who is worried about my grades, ends up staying after class alone with me...