Ichihana Oshino (32) is a beautiful and voluptuous teacher at the school that Taichi attends. One day, while in class, as Taichi was fantasizing about Ichihana-sensei, his classmates caught him and started teasing him. To save face he made a comment to his teacher. Embarrassed by the words he said, Taichi skips school. The next day, Ichihana-sensei, concerned about Taichi, comes to visit him. "Taichi-kun, you're more mature than the others, so I've prepared a special lesson for you." Ichihana-sensei quickly takes off her jacket, revealing her large breasts. Unbeknownst to Taichi-kun, Ichihana-sensei is a former porn actress who loves sex, with the belief that sex should be given openly and freely! Let the Ecchi lessons begin with Ichihana-sensei's first lesson, "One plus one..."!