Shigeno Goro (born Honda Goro) is the protagonist of the series. The anime is centered on his baseball career from pre-school to adulthood, while emphasizing both sports as well as dramatic events.
The first part of Season 1 starts off with Goro living with his father Honda Shigeharu, a young widower and baseball player. Both of them share a great passion for baseball and affections for Goro’s nursery teacher, Hoshino Momoko. They live in Mifune-cho, Kanagawa Prefecture.
Shigeharu is a struggling second-string pitcher playing for the Yokohama Blue Oceans, and is on the verge of losing his job due to an injury. Goro becomes disillusioned with baseball when confronted with this, to the point that he wants to quit playing himself. But instead, he sneaks out of his nursery to beg passionately with the management of his father’s team, the Yokohama Blue Oceans.
This prompts Shigeharu to become become a fielder and batting specialist, with great success. When Goro sees his performance, his faith in baseball is also renewed.
Goro befriends a local boy, Sato Toshiya and they try to the Mifune dolphins, a local Little League team. Shigeharu strongly objects to this, as the risk of injury and permanent damage at their young age is very high.
Tragedy befalls Goro when his father dies as a result of a beanball to the head. Although his uncle offers to take him, he chooses to be adopted by Momoko, who at this point had become Shigeharu’s fiancée. Together, they move away to another prefecture. The anime omits 3 years at this point.
Afterwards, Goro, who is now 9 years old and therefore eligible to play in Little League, returns to Mifune-cho. Ando, the aging coach of the Mifune Dolphins, who had already been impressed by Goro’s skill three years earlier, is delighted to see him return. However, the Dolphins barely have any members left and are on the brink of collapsing.
Goro tries to persuade his classmates to join the team, but nobody seems interested. He is eventually joined by Shimizu Kaoru, a strong-willed girl, and Komori Daisuke, whom they save from being bullied. Also, Sawamura, a boy who had previously bullied Komori, joins them after seeing the error in his ways.
The four of them barely manage to complete the Dolphins, but are faced with an unreasonable challenge: to be allowed to use the baseball field, they must win a game against the Mifune Attacks, a sandlot team of adults. Goro gladly accepts, eager to show off his skills.
It turns out, however, that Goro had underestimated the adults. His pitches keep getting hit and the inexperienced fielders don’t support him very well, resulting in a tense argument with his teammates. Momoko finally intervenes and scolds Goro for his selfishness. Goro eventually realizes that baseball is a team-based sport and he must trust his teammates.
The match results in a very close loss, but the adults, impressed by their performance, choose to support them and grant them practice time on the field. Ando realizes, however, that Goro’s talent is wasted on his mediocre team and sends him to visit Yokohama Little, a rival team.
There, Goro meets his childhood friend, Toshi. He subsequently demonstrates his pitching prowess and is asked to join YL. He initially refuses, but then discovers his father, Shigeharu, had played for YL in his youth. Wishing to follow in his father’s footsteps, he decides to join YL. This leads to a heated argument with his stepmother, as she does not want him to abandon his friends and teammates from the Dolphins. She turns to Shigeno Hideki, a teammate of Shigeharu, for advice. Also, she suddenly becomes ill and coughs up blood, collapsing in Shigeno’s arms.
When she is hospitalized, Goro, who has already suffered the loss of both parents and is now fearing the worst, realizes that the living are more important than the dead and decides to stay with the Dolphins after all.
Kusakabe, a translator affiliated with the Tokyo Warriors and Joe Gibson (the man who had beaned and killed Shigeharu 3 years prior) shows up and invites Goro to watch an All Star Game in the American Major Leagues. Goro, who still resents Gibson, promptly refuses. Kusakabe proceeds to explain Gibson’s hardships and is able to persuade Goro to travel to the U.S. after all.
Together with Shimizu, he travels to San Francisco to watch the All Star game. Gibson boldly announces that he will only pitch fastballs, and strikes out 5 batters consecutively. This makes Goro very proud of his late father, as he had been able to hit a homerun off of Gibson’s fastest pitch. After the game, Gibson gives Goro the opportunity to “take revenge” by purposely beaning him. He accepts, but deliberately misses, stating that his pitches still lacked power and promising that he would challenge Gibson when he has grown up.
Impressed by the Major Leaguers, Goro decides to up his team’s level a notch and convinces the Dolphins to join a training camp. Even with an injured left arm, he stays very confident and is quick to challenge other teams. In the first practice game, the Dolphins are up against Kuki Little, a team that boasts a “genius batter”, Kamigauchi. Goro quickly manages to strike him out, but as the game progresses, he accidentally hits a runner while fielding. He cannot control his throws properly afterwards, and it turns out that he has an intense phobia of deadballs due to the trauma resulting of his father’s death. The Dolphins end up losing the match.
Goro realizes his problem and challenges Yokohama Little in an effort to overcome his phobia. Initially, it seems like he has been cured, but subconsciously, he can only throw low and outside, away from the batter’s body. Coach Kashimoto from YL acts as umpire, and deliberately calls all his throws as balls. He goes even further and provokes Goro to the point of mocking Shigeharu as “a fool who couldn’t dodge a pitch”. Furiously, Goro throws a ball at Kashimoto’s head. Kashimoto purposely takes the hit, showing that Goro’s ball can’t really hurt him at the current speed. He also reveals that he was actually teammates with Shigeharu in Little League and respected him deeply. He convinces Goro that his father’s death was a tragic accident, but that he mustn’t stay depressed about it. Goro manages to overcome his fear, but Kashimoto ends the match afterwards, stating that the lone fastball in Goro’s repertoire isn’t enough to challenge them.
As the training camp proceeds, he meets Kawase Ryoko, a slightly older girl whom he becomes quite smitten with, partly because she reminds him of his mother and stepmother. When he discovers that she is a pitcher for Yokohama Little, he develops a serious crush on her, much to the annoyance of Shimizu. He remarks remarks that she is completely different from Shimizu, who is terrible at playing baseball, which prompts Shimizu to leave the team. Goro soon discovers that Shimizu is actually very passionate about baseball and is able to convince her to come back.
The training camp ends and soon afterwards, the summer tournament begins. The first opponent is Honmoku Little, a team that is centered around the Okamura triplets (Ichiro, Jiro, Saburo), the self-styled Black Triangle. The three of them form a seemingly impenetrable defense, and with individual strengths while batting, manage to put Goro under a lot of pressure. Halfway through the game, Goro is about to give up when he is revitalized by the performance of Shimizu. With a combination of willpower and some luck, the Dolphins manage to catch up at the bottom of the final inning.
Shigeno Hideki begins to pursue a romantic relationship with Momoko, which she tries to hide from Goro. He notices anyways and becomes very angry with her at first. He is afraid that she might abandon him if she should choose to marry Shigeno, as they are not related by blood. When he realizes that she is serious and how lonely she has been ever since Shigeharu’s passing, he manages to come around and gives the relationship his blessings.
The summer tournament continues, with Totsuka West as their next opponent. Similar to the Dolphins, they are a one-man team led by Usami Kyuta, a sixth-grader who can pitch perfect forkballs. His personality is in stark contrast to Goro’s, since he plays very detached and solely for the sake of his father, the domineering coach of the team. After Komori gets injured early and has to be subbed by Goro (with Sawamura as pitcher), the Dolphins fall behind quickly 0-5, but manage to keep the score throughout the game. Once again, they manage to turn it around at the bottom of the sixth (and final) inning.
Their third game is against Yokohama Little, which had dominated the previous games to the point of winning by mercy rule. The Dolphins resign mentally, seeing how it seems like a hopeless endeavor. Komori’s more permanent injury only adds to this feeling. When Shimizu, the only girl on the team, takes over the catcher position, they decide to give their best after all.
The day before the game, Goro meets Toshi and Ryoko. She explains her passion about baseball and while expressing her admiration for Joe Gibson in particular, inadvertently speaks ill of Shigeharu, as she thinks that Gibson’s career was “destroyed” by the latter’s failure to dodge the deadly beanball. They manage to reconcile soon afterwards, but part to become enemies in the upcoming match.
The Dolphins, completely unified by Goro’s passion, arrive in the Yokohama Ocean Stadium (home ground of the Blue Oceans) for the match. Intimidated by the big stadium, they make many mistakes and quickly fall behind, giving up 9 runs in the first inning.
After practicing intensely against curveballs, they manage to hit well against Esumi, YL’s ace pitcher, quickly scoring 4 runs. This motivates the whole team, and the performance on defense improves as well, managing to keep the score at 4-9. YL sends in a new pitcher, Kikuchi. His initial confidence in his fastballs is crushed when the Dolphins hit them very well, being used to Goro’s faster pitches. They score 3 runs, and just when it seems like Kawase Ryoko may be subbed in, Toshi is brought in as catcher instead. He proves to be a big challenge, purposely provoking the hot-headed Goro to make mistakes.
After getting used to Goro’s speed, the YL batters manage to land some hits and put him under severe pressure. Suddenly, Goro reveals his trump card: a high-level change-up, which, in combination with his fastballs, manages to hold YL back significantly. The match turns into a battle of attrition, with no change in score until the bottom of the sixth. Komori manages to pull off a hit despite his injured hand, and with the Dolphins scoring 2 runs, the game proceeds into extra innings.
The players from YL now employ a delaying tactic, trying to tire Goro out, seeing how he has no relief pitcher. They do so with success, to the point that Goro is on the brink of collapse. But despite Shigeno’s intervention, Goro refuses to leave the mound, as he is determined to see the game through to the end, after all the sweat and blood his teammates had poured into their training. His contagious fighting spirit ultimately prevails, and the Dolphins are victorious. However, after overburdening his shoulder for too long, Goro is forced to rest and undergo rehabilitation for a few months.
He still continues to practice secretly, but is caught and confronted by Shigeno. Shigeno reveals that he was the one who pushed Shigeharu into becoming a batter, therefore partly responsible for his death, and fears that Goro would follow in his father’s footsteps, recklessly destroying his future career as an athlete. The two of them manage to sort things out, and Goro accepts him as a father-figure. Momoko becomes engaged to Hideki, and they marry half a year later.
At the wedding, Goro reveals to Ando in confidence that he will be leaving soon. He shows up to greet the new Dolphins team members in the following spring, but secretly skips town after saying an ambiguous goodbye. It is only when his fellow classmates enter the fifth grade that they are told how Goro had moved away, as Shigeno Hideki had been traded to the Fukuoka Falcons.
Season 1 ends at this point and Goro promises to return one day.