Based on the light novel.

This is real pro baseball! Ishihara (Mercy), a 2nd-string pitcher on the brink, has pitched as the 1st string zero times in the 3 years since he went pro. Just as he's wondering if he'll finally be cut from the team, his F-cup girlfriend presses him to “retire and take over the family business”. In such a corner, an offer comes to Ishihara from the 1st string! Can he seize the chance!?

The slugger who signed a 3-year contract worth 1 billion yen after transferring as a free agent became the villain of the baseball world! However, the man known as Samurai aims for solitude as a pro baseball player.