Kuritaro Kuriyama , a second-year student who transferred to Daiichi Junior High School, joins the junior high school's baseball team because his left arm throws a fastball and quickly becomes the ace . Overcoming the feud with the former ace of Kuritaro, the baseball club makes it through the qualifying rounds for the national junior high school baseball tournament, and Kuritaro creates a magic ball, a rocking curve.

At the national tournament, Miyamoto Musashi's ``Tama-tama ball'' thrown in rough seas, one-armed Tange Uzen's "Iai throw'', and Kojiro Sasaki of Iwanagare Junior High School's "Tsubame-uchi batting method'' were performed. They will compete against strong teams from all over Japan.