Onoue Nozomu and Yura Nodoka are childhood friends who live in the same neighborhood.

They have been playing together since they were littl, and like to compete with each other in various things such as amateur wrestling, running and more. Basically, anything that can be compete, even to this day and before they knew it, they have reached an appropriate age.

Somehow, they became aware of each other as a man and a woman...?

Then with a slightly different flow than usual, they decided to compete in sex matches. After that, they realized their feelings for each other and have a happy ending... Or so it would seem, but it didn't happen.

In the end, both of them were so determined to win, competing in "who can make the other person cum first" or "who can make the other person feel better".

And thus, the endless sex battles for the two of them begin.