"Shimizu Anya is the daughter of the two former top Tennis Players of the world. And now, it's her time to conquer the domain of Professional Tennis.
Until her destined rival came, who completely crushed her before she could even step out to the outside world. This is where their one-sided rivalry begins." - Official synopsis.
Shimizu Ayane, 19, won the Battle of the Sexes Grand Final 2016 against of opponent Nathan Greene, 25. After the match, both tennis players retire and marry, settling down in Ayane's hometown in Kyoto, Japan.
Their daughter, Shimizu Anya, is determined to be the best tennis player just like her mother and father. Nathan is rarely around due to him working in Tokyo, so Anya grew up with a strong mother-figure.
One day, Anya goes to visit her father in Tokyo. There she meets Koizumi Axel, Nathan's disciple. Anya also overhears her father admit that he purposely lost the Battle of the Sexes Grand Final 2016 so that Ayane can win -- the reason why Ayane and Nathan are no longer on good terms.
Wanting to prove her mother is the best tennis player, Anya challenges Axel to a best of three match. The loser of the challenge will have to "follow one absolute rule" set by the winner. Anya says she'll make him quit tennis forever and Axel says he'll make her his personal stripper.
Meanwhile, Nathan and Ayane make up.
Eight years later, Anya is now sixteen and has been training under her mother for her match with Axel. Axel and Anya meet once again, and Anya seems to have grown a crush on him.
Before their match, Nathan tells Anya that before he and her mother got married. She had a boyfriend and he had a fiance, and in short, they stole each other from their respective partners. As well, Axel asks to "borrow" Anya no matter the results of the match. Nathan reluctantly agrees, and Anya is bashful at the thought of going to Tokyo with Axel. But before that, Ayane challenges Axel to a tennis match. If he wins, he can take Anya and train with her in Tokyo. But if Axel loses, Axel will have to quit tennis.
Axel pranks Anya by nearly kissing her, and snapping a selfie of her, "horny", expression.