After the death of her husband Kenichi, Natsuko is discovered to have a talent for baseball by Shigeno, the manager of the grass baseball team "Tamagawa Mets. This marks the end of her life as an ordinary housewife who had been a chaste wife. In order to pay off the debt left by Kenichi, Natsuko becomes a pitcher for a grass baseball team, and as she trains hard with Shigeno, she becomes obsessed with the pleasures of baseball. Accompanied by her sister-in-law Haruyo, a professional baseball scout named Furuta, and other characters with one or two peculiarities, Natsuko makes her way through her life...

夫の賢一が亡くなり、草野球チーム「多摩川メッツ」の監督である重野に野球の才能を見いだされた夏子。そのことから、貞淑な妻であった彼女の、ごく普通の主婦としての生活は終わりを告げる。賢一の残した借金を返済するため草野球の投手を務めることになった彼女は、重野とともに激しい特訓を重ねるうちに、野球の快楽性にとりつかれていく。義妹の春代やプロ野球スカウトマンの古田ら一癖も二癖もある人物たちに囲まれ、夏子は歩みを進めていくが……。