Loner Tsukuyo Kagemoto is on her daily search for a spot to eat lunch when she notices an unused classroom and tries the door. To her surprise, she finds her classmate Tomoka Hinoue touching herself. Caught looking, she tries to run away, but Tomoka stops her and makes a surprising offer.

"If you do something naughty with me, I'll let this slide."

Bowled over by an enthusiastic Tomoka, Tsukuyo gets caught up in a secret tryst.