伯利沙利文是个害羞的送奶工,他一不小心撞了醉酒的麦克法兰,一个冠军的拳击手,同时也是欺负伯利妹妹的人,两人争执起来。当地报纸报道了伯利沙利文的厉害,并附上了照片,所以俱乐部经理决定把伯利培养成拳击手。伯利没有意识到,他的对手已经要求对决,因为对手以为他真的是一个伟大的战 士,同时伯利与漂亮的夜总会歌手波利普林格尔感情迅速升温。他可能会最终得到他应得的惩罚,如果他没有赢得这场对决。Shy milkman Burleigh Sullivan accidentally knocks out drunken Speed McFarlane, a champion boxer who was flirting with Burleigh's sister. The newspapers get hold of the story and photographers even catch Burleigh knock out Speed again. Speed's crooked manager decides to turn Burleigh into a fighter. Burleigh doesn't realize that all of his opponents have been asked to take a dive. Thinking he really is a great fighter, Burleigh develops a swelled head which puts a crimp in his relationship with pretty nightclub singer Polly Pringle. He may finally get his comeuppance when he challenges Speed for the title.