Maruo Eiichiro is an honor student in his first year of high school. He's a very methodical person who keeps two sets of notes for class and focuses entirely on his studies. One day, Eiichiro decides to participate in a free trial at South Tennis Club (STC) because he needs some exercise. There, he meets school idol and sweetheart Takasaki Natsu. Eiichiro has taken his first step into the world of tennis

Eiichiro is unable to answer Natsu when she asks him what he enjoys doing most. He becomes interested in tennis and returns to STC for another free trial.

Eiichiro is unable to forget how good it felt when he successfully returned Takuma's serve, and he spends all of his time practicing against the wall. After seeing Eiichiro practice against the wall non-stop for six hours on a Sunday, Natsu predicts that he will quickly improve.

Eiichiro finds himself in a contest with Takuma. Eiichiro has fifty tries to return Takuma's serve. One successful return and Eiichiro wins. However, despite Eiichiro's best attempts to follow his notes and stick to the basics, he can do nothing against one of the strongest serves in the country.

Eiichirō is about to play his first match. He receives advice from the other STC members, but it only makes him more nervous. He doesn't get a chance to calm himself down as he's soon called to the tennis court.

It is down to the final match of the set. Eiichirō trails 5 games to 1, but with a determination to stay on the court as long as possible Eiichirō begins to push Oobayashi.

In order to improve Eiichirō's playing, Coach Miura has him learn control on a 9-square court. After getting the basics done, Eiichirō is forced into a match against Takuma.

Maruo Eiichirō continues his training at STC as he tries to master every shot. At smaller tournaments he begins advancing to the third round but is unable to go further. His mother worries that Eiichirō is spending too much time on tennis when he drops out of cram school to practice more.

Eiichirō returns to the Kanagawa Junior Circuit. His first match is up against fellow high school student Koshimizu Nariyuki, a man whom is always trying to compete with Eiichirō for the top scores.

The match between Eiichirō and Miyagawa begins with each holding serve. However Eiichirō feels that something is off. After studying his notes, Eiichirō realizes that Miyagawa has been studying his shots, and with a 4-3 lead he plans on making his move in the eighth game.

After managing to hold serve Eiichirō starts looking for an opportunity to break Miyagawa. Both hold serve and force a tiebreaker. With the score 6-5 Maruo in the tiebreaker Eiichirō decides to try and gamble to use his full stroke and steal a point.

After defeating Miyagawa, Eiichirō returns to STC for some training that will make him better in 1 day. Eiichirō is teamed up with a Coach Mike from Florida who specializes in pyschological training.

The match between Hiromi and Eiichirō begins. Everytime Eiichirō tries to go on the attack, Hiromi hits a shot Eiichirō can't reach.

It is match 10 of a 1-set match, and Eiichirō leads 5 games to 4. Eiichirō begins to up his speed against Hiromi, and with it he stays even at 30-30. Just then Hiromi's legs cramp up, allowing Eiichirō to get two easy aces and win the match 6-4.

Eiichirō overhears Araya telling Takuma that if he loses to him this tournament, he will retire from tennis. His plan is to defeat Takuma and then announce he is going pro. Takuma agrees to tell Eiichirō Araya's weaknesses.

After going up Love-15, Araya uses a number of service aces to go up 3-1 in set 2. Eiichirō holds serve, and as he gains a 30-40 advantage in Game 6 of Set 2, Araya punches himself in his face to eliminate his emotions from the game.

Araya and Eiichirō end up at deuce after neither player can gain an advantage. An ace end up being huge for Araya give him the match point advantage, and despite his best efforts a lucky bounce proves to be the end for Eiichirō as he loses 6-1, 6-4. The finals are held between Araya and Takuma.

Eiichirō investigates going Pro, but his reaction from his parents is less than he expected. Eiichirō joins Natsu at the first round of the All Japan Pro to watch the debut match of Ike Souji.

Eiichirō manages to steal 1-point in the 10-minute match with Ike before his coaches reappear and make him stop playing a match. Afterwards Eiichirō is sent home to rest. The next day Eiichirō begins a brutal practice regimen that will recondition his body into that of a pro's.

Eiichirō participates in a tournament after 3 months of hellish training. He learns about active rest while participating in the tournament and makes it to the final. Terashima is his opponent.

Eiichirō continues his practice and gets his next tournament schedule. As the last player to qualify he is placed up against the 1-seed, Yu Nabae. Eiichirō begins to look for weaknesses from Yu on tape, but what he finds is a highly adaptive style that could easily beat him if he doesn't come up with a few tricks.

Yu Nabae matches up with Eiichirō and realizes they really are two players that are virtually the same. He realizes that what Eiichirō lacks is experience with the fundamentals, as he has never played anyone like himself, and after losing the first set Nabae begins to pull away and goes up 5-2.

In an effort to try and reverse the tide, Eiichirō decides to go back to his idea of having 100-squares to aim for instead of 9.

Eiichirō runs to watch Natsu's match when he learns she is in danger of losing. Afterwards they return to STC where he Ryuhei Aoi, a man who will become his new coach.

Eiichirō and Natsu go out on their first date. When Eiichirō asks Natsu what she thinks about him, she tells him he is cheating. Afterwards Eiichirō is allowed to resume practice.

Eiichirō arrives in Florida, and Coach Mike introduces him to Marcia, an upcoming junior whose older brother just made the Pro's. Marcia and Eiichirō play a match, and Marcia decides Eiichirō must be training for the French Open because of his slow play style.

Eiichirō begins closing the gap on the others at the Florida Academy, but during everyone of his matches he has one moment where he presses too hard, costing him a set and eventually costing him the match.

After winning his first match in America, Eiichirō finally gets to play Ike in a one set match. Ike gets it approved at the New Years party where many of Eiichirō's new friends first learn of Natsu.

In his final day in Florida Alex agrees to play a best-of-3 match with Eiichirō. Alex realizes that Eiichirō's notes contain all of his weaknesses and that he will have to adjust his play style to win the match.

Eiichirō returns from Florida and is given a day off to adjust his body to the time difference. After the day off Eiichirō begins a new strict training regime to help him get ready for the Kanagawa Prefectural.

Coach Aoi explains to Eiichirō that he stopped the match against Takuma because his body wasn't developed to serve like Takuma yet. If he had continued to serve that way, he would have injured himself and forced himself to give up his tennis career.

The Kanagawa Prefectural begins as Eiichirō faces off against Araya's new underclassman Nishimura. Araya has told Nishimura all of Eiichirō's weaknesses from the year before, making Nishimura very confident in his chances of winning.

Eiichirō and Miyagawa face off in the second round of the tournament for their second match. If Eiichirō loses he knows he'll lose all chance of going pro. If Miyagawa loses he knows his path to become a pro will take longer and might force him to go to college first.

Coach Ryuhei Aoi decides to teach Eiichirō the importance of relying on instincts during a match instead of relying solely on data. In order to teach him how to play against a player who relies solely on instinct Eiichirō is forced to face off with Natsu.

Araya and Eiichirō begin their match in the Kanagawa Prefectural Final. At first both are holding serve and the score is at 3-3. However Coach Aoi realizes Eiichirō doesn't have the knowledge on how to deal with left handers since he's only played Araya once.

Eiichirō throws out a couple of unexpected dropshots in set 2 and begins to alter the speed of his game. After trailing 30-love to begin match 2 of set 2 Eiichirō is able to rally with this new strategy and pull off a break.

Araya and Eiichirō prove to be even and are both unable to break each others serve. Making things worse is there will be no tiebreaker., Instead an individual must win by 2 games.

The gang begins their third and final year of high school in different classes. Eiichirō and Natsu both realize their classes seem to be moving on without them as they are getting ready for cram schools and entrance tests.

The final door on the way to the All-Japan Junior, the Kanto Junior Tournament, is just around the corner. Eiichiro psyches himself up as he confirms his promise to his parents that he'll give up if he doesn't win the All-Japan Junior, and then he sets off with the other STC members for Chiba, where the Kanto Junior will be held.

The Kanto Junior Tennis Tournament begins at last, and Eiichiro is facing Yakabe Tadanori in his first match. Although he had watched videos of Yakabe's matches from a year ago, Eiichiro is bewildered by his opponent's much taller stature and completely different play style, and all the unexpected factors lead him to consider blanking all his mental data and starting from scratch.

Eiichiro is stunned by all the cheering Ide receives as their match begins. He struggles with the unpredictable plays of the intuitive Ide, but he recalls what he learned in his match with Natsu and concentrates on watching his opponent. Meanwhile, Ide also struggles to keep up with Eiichiro's constant changes in tempo and starts to tune out the world as he tries to focus.

Ide's remarkable ability to adapt instantly to everything has Eiichiro struggling, and reads his notes again to regain his focus. This improves his movements and leads to more impressive rallies, making the match even more exciting. Neither is willing to yield as the match comes down to which player can manage to hold serve...

Eiichiro thought he was successfully ignoring the crowd's roaring cheers for Ide, but his body was reacting to it more than he realized. The pressure of playing in front of a dramatic, Ide-centric crowd is troubling Eiichiro.

Eitaro, upon winning spectacularly in his fight against Ide, decides to go to the National Junior's. Coach Aoi explains that towards the end of the match, Eitaro was completely in the zone.

The match against Takagi begins. Just as Yukichi warned, Takagi's style is unique.

Even if it seems to lack etiquette, Takagi's play style continues to work in his favor by disupting his opponent's pace. Eiichiro struggles to deal with Takagi's tactics.

After beating Takagi, Eiichiro moves onto the semi-finals as does Natsu in the women's division. Eiichiro becomes aware of new feelings towards Natsu while watching her match.

The match has just begun and Eiichiro is already close to being in the zone. His excellent condition is reminiscent of his match against Ide; Eiichiro doesn't give Nabae a chance to fight back and soon takes the lead.

The match between Eiichirou and Nabae finally reaches its thrilling climax, and the former risks losing to envision his victory.

The game finally reaches its final stage. Eiichiro who desperately envisions a vision to win Nambae and is ready for a new strategy with the intention of losing.