The hallowed ground of Koshien Stadium is the "field of dreams," where the ambitions of high school baseball players come true. After emerging victorious in the autumn tournament last year, Seidou High School baseball's team has finally earned the right to compete there for the first time in seven years. Beyond the spring tournament looms the battle to decide who is the best team in the nation — the Summer Koshien. With the third-year players due to retire after the summer tournament, the team has to integrate the experience of the seniors and the potential of the newcomers to overcome familiar and new opponents alike and win the coveted national title. Meanwhile, pitcher Eijun Sawamura is as determined as ever to earn jersey No. 1 and seize the position of "ace" from his persistent rival, Satoru Furuya. As the team prepares for their greatest challenge yet, Sawamura and Furuya carry on their struggle to lead their team to glory and become the star of the game: the true "Ace of the Diamond." [Written by MAL Rewrite]

Sho liked MTB very much and he always practiced at the practice field, “X-Zone”, with his friends, Takumi and Makoto. Takumi was a good mechanic and Makoto was a competitive girl rider. One day, he was challenged by a MTB team, “Shark Tooth”, of Samejima brothers’ betting the X-Zone. For Sho, X-Zone was a memorable place where he had spent days with his dead father, and he couldn’t lose the game. The day came, and during the race with the leader of Shark Tooth, black smoke suddenly covered around, and they were sent to another world. When he came to, he found Kakeru, Makoto, and his MTB, “Flame Caesar”, were also there. While they were wondering what had happened, MTB riders came. They challenged Sho to a MTB bout. They said Sho had to collect 10 pieces of emblems by winning MTB bout, “Idaten Battle”. This is how Sho came down to compete in Idaten Battle at various courses, such as, volcanos, ruins, deserts, snowy montains, and grave yards. Whether will show win the race to come back to his world?

As a young child, Aizawa Yuuichi had often visited his cousin in the city; however, something drastic happened to keep him away for seven long years. Now, Yuuichi returns, his memories of those days are simply gone. Settling into the wintry town, Yuuichi comes across several young girls, all of whom are connected to his past. As he befriends them and continues to interact with them, the long forgotten memories from his childhood begin to resurface... [Written by MAL Rewrite]

With their school's pool opening the next day, Iria schemes up the idea to hold a swimsuit contest. With Lisara, Mina, Quele, and Iria herself all participating in the event.