The series, set in Saitama, follows the story of Ren Mihashi. Mihashi was the previous ace pitcher in his middle school's baseball team, but it seems that he only got the position because his grandfather was the owner of the school. His teammates (especially the team's catcher) hated him, and they always lost their games. Mihashi is thoroughly convinced that he is a lousy baseball pitcher and he graduates through middle school with extremely low self-esteem. He then transfers to Nishiura high school with plans of quitting baseball, because he does not believe he is good enough to succeed at baseball. However, he is dragged into Nishiura's baseball team by their coach. Assisted by his new teammates (and especially the catcher, Takaya Abe), he grows in stature, confidence and skill, helping his team excel with his own abilities.
This story has the part which was created by referencing Wikipedia, so the licence of GFDL is applied to this story.