Akanagi High School is a prestigious school with boys' and girls' volleyball teams that have reached the national level of competition many times.

"Mitsuki Okamoto" is the ace of the girls' volleyball team, together with "Kazuya Karasutani" from the boys' volleyball team. The two of them are acknowledged by the people around them as a couple, but neither of them has had any sexual experience yet.

One week before the inter-high competition, on a certain day after club, the two of them were making out in an empty clubroom. They locked the door and unable to hold back any longer, Karasutani says he wanted to do it right then and there...

"I don't want my first time to be at school... My parents said they'll be going on a trip on Saturday next week, so it's fine to do it then..."
Karasutani is overjoyed from just this suggestion by Mitsuki.

However, the two of them didn't realize, the curtains were slightly open...

The next day, Mitsuki is called upon by the coach named "Takeda" and informed about a certain "problem making the rounds". He shows her a certain image and threatens a two-week suspension plus a possible withdrawal of their sports scholarship.

Mitsuki begs him for an exemption, but what will coach Takeda demand in exchange...?