Ryouma Echizen is one of 50 nationally ranked middle school tennis players to receive an invitation for the Japan U-17 tennis training camp. Previously open only to high school players, the exclusive regiment trains the best players in the country for the upcoming U-17 World Cup. The high schoolers are not pleased that these middle schoolers are allowed into the camp, but the middle schoolers easily overwhelm them before they are halted by the coaches.

The rules of the camp are soon explained: the players are split into one of 16 courts based on skill, with the best players occupying Court 1. Players move up and down courts based on "shuffle matches" that occur before practice begins each day. In anticipation of a game, the middle schoolers are asked to pair up with one another, only to find out that they would not be playing doubles with their partners. Instead, they are pitted against each other in a tiebreaker-style game. The winner of the match would be allowed to stay to further develop their skills whereas the loser would be sent home.

For the sake of tennis, friendships and camaraderie are all put on the line. As the fierce competition between the middle and high schoolers persists, the situations they find themselves in goes deeper than just playing to remain in the camp.