Casey lives with his sister and works in Hicks' general store and post office. The greatest thing in his life is his love for his little niece. To the people of Mudville, Casey is a hero because of his ability to win ball games for their team. Casey is a slugger of worldwide renown, but off the ball field his uncouth ways deprive him of the friendship of any but a half-wit, who follows him around, and the little children to whom he is a hero. Casey develops a love for Angevine, daughter of Judge Blodgett, but she is in love with Bert Collins, who has just returned from college and has been engaged as a pitcher for Frogtown, Mudville's greatest rival for baseball honors. In the meantime Hicks takes to robbing the mails. Casey becomes suspicious of him and about the time he finds evidence of Hicks' guilt, a stranger comes to town. The second game of the big series between Mudville and Frogtown goes to the latter because Casey, who has burned his hands at a country dance where he carried out an oil lamp that exploded, cannot play. But the final game arrives and Casey is ready. Bert is up against it because Angevine's rather has told him he must be able to show $2,000 before he can hope to win his daughter. He gets his mother to mortgage their home and with the money she lends him, he bets with Hicks on the final game. Just before game time, Casey sends word he can't be there because his little niece has fallen from a tree and is dangerously hurt. Hicks is in despair and rushes to Casey's house, only to be kicked out. In the meantime Frogtown forges ahead and the crowd yells for Casey. Casey finally consents to go and leaves the half-wit to watch at the little girl's bedside. He reaches the grounds in the last half of the ninth inning. Mudville is two runs behind; there are two out and two on base. Casey goes to bat. Just at the moment when the pitcher is getting ready to throw the third strike, for Casey always allowed two strikes to be called, the half-wit enters the grounds. Casey sees him, thinks the little girl is dead and strikes out. But the little girl is better; her father, who has been away, returns. Angevine is happy with her lover; the town turns on Casey as a fallen hero and with nothing to hold him, he packs his effects in a little bundle and trudges down the railroad tracks away from the town that has been his home all the years of his life.