Ki ni Naru Class no Joshi ga, "Ana" o Shiteiru Rashii.

"A slut in a cardboard box appears in an unused room in a certain building."

"The cardboard box has a hole on its front side and she shows only lower
half of her face through the hole and gives kisses and blowjobs."

Having overheard such rumors, a schoolboy Rokurou
comes to have a strong desire to see that woman.

On the other hand, he also has some feelings for
a classmate Mizore Yukishizuku.

As he goes to the building repeatedly, he finally faces the truth of that woman...