Yui Narukawa masturbates in the classroom after school.
She is the most beautiful girl in the school, with excellent grades, neat and gentle.

Tomoki Inomiya, a man who cannot refuse her, happens to take a peek at her.
He tries to quietly leave the scene, but Yui notices him.
He asks her to keep it a secret.

The next day, after school.
Yui asks Tomoki for a favor again.
The contents of this request are…

“My masturbation ……!　I want Inomiya-kun to see it!