The heroine, Kasuga, recently grow a curiosity about men. The curiosity about the important part of the men, the desire of witnessing what men look like down there. One day during an exam, she can’t concentrate at all because she’s the only girl in the class, and because of that her curiosity getting dramatically stronger. The exam’s ended without Kasuga answers a single question. Her childhood friend who also has a crush on her, Kobayashi, was shocked to see Kasuga getting zero points from the exam. At the same time, he brags about his perfect score on the exam. Then Kasuga decide to challange him. The one who scores better has to fulfill the winner’s order. Under lewd motivation, Kasuga studies hard in order to fulfill her curiosity.