One day, the protagonist wakes up in an unfamiliar room. For some reason, a schoolmate from a higher pecking order, Akino Yuna, is next to him.

Still confused, he tries to look for a way out, but with no success. There are only white walls and a single bed, a room with nothing. At the same time, Akino Yuna wakes up, unable to hide her confusion as well.

For the protagonist, who has nothing to do with her, this situation is unbelievable. However, in the meantime, there is an announcement.

"Well, then, please begin having sex."

The sudden announcement makes them freeze.
What is going to happen to them?

[Translated and edited from the official website]