Suzuki Aoba, a gloomy high school freshman who is occasionally beaten up, one day he is saved by Akasawa Kenshin. Aoba enters the world of "MMA" aiming to reach the top spot of a tournament to determine the strongest high school fighter.

Suzuki Aoba, a gloomy high school freshman who is occasionally beaten up by classmate Iwase Sannosuke. One day, he is saved from the "play fighting" by Akasawa Kenshin, a superstar in the martial arts world, who suddenly says to him, "You're empty". After being introduced by Sannosuke, Aoba enrolls in the Shark Gym, run by Tokiwa Kanenari, and enters the world of "MMA" (mixed martial arts). Under the guidance of his master, Amachi Wataru, he aims to reach the top of "MMA Koshien", a tournament to determine the strongest high school fighter. A group of eccentric athletes, including Tamamatsu Kota, Hazuru Yuga, Nueji Ganmaru, Hiiragi Amu, and Hachiya Mamoru, await Aoba.