Ren Mihashi was the ace of his middle school baseball team, but because of his poor pitching, they could never win. Constant losses eventually led to his teammates bullying him, reaching a point where they no longer tried to win, which caused Mihashi to graduate with little self-esteem. As a result, Mihashi decides to attend a high school in a different prefecture, with no intention of playing baseball. Unfortunately, upon arriving at Nishiura High, he is dragged into joining their new team as the starting pitcher. Although unwilling at first, Mihashi realizes that this is a place where he will be accepted for who he is; with help from the catcher Takaya Abe, he begins to gain more confidence in his own abilities. Abe, seeing potential in Mihashi, makes it his goal to help him become a pitcher worthy of being called an ace.