Cuarta película basada en el manga/anime de Mitsuru Adachi. Tatsuya y el Meisei por fin consiguieron hacer realidad el sueño de Minami y de Kazuya de ganar en el estadio Koshien. Pero la vida no acaba después de conseguir un objetivo. Todo sigue, pero parece que Minami y Tatsuya aún no están preparados para sincerarse el uno con el otro. Viejos conocidos y, sobre todo, una chica del pasado, no le pondrán las cosas fáciles, el amor no es un juego donde se gana o se pierde.
Due to sickness, the coach position of the Meisei High School baseball team is handed to Eijiro Kashiwaba. He is a ruthless man who forces the team to enter a Spartan training procedure. Tatsuya and Minami slowly discover stories about his past and wonder what his true intentions are.
Tatsuya and Minami meet Akio Nitta, an ace batter who thought of Kazuya as his rival. Nitta sees great potential in Tatsuya and expects to face him on the road to the national high school baseball tournament.
Tatsuya Uesugi is the twin brother of Kazuya, pitcher of the Meisei High School baseball team. Irresolute about his feelings towards baseball, his next door neighbor, and his brother; Tatsuya ends up joining his school's boxing club. From the sidelines, he quietly watches the ascension of Kazuya.
Megazone 23 se desarrolla en un futuro distante, a principios del siglo 24. En esta época, varios problemas ambientales hicieron que la Tierra fuera inhabitable. Los humanos empezaron a abandonar la tierra en gigantescas colonias espaciales llamadas Megazones. La animación se enfoca en los habitantes de la colonia Megazone 23 (de ahí el nombre)
Just before entering Seishuu High School, track star Katsuya Niimi and judo champion Susumu Karasawa see a girl crying as the school loses a baseball game. The boys decide to join the team and improve it in order to make her smile. The girl turns out to be Yuri Nakao, daughter of the baseball coach, and they learn the baseball team will be shut down if it doesn't start winning. The series follows the three, as well as pitcher Eiji Kurahashi, as Niimi and Karasawa learn about baseball and what it means to be one of nine players on a team, as they work together through high school make it to Koushien.
