Knockout Kelly, a champion pugilist, steals the cashier of a beanery from her sweetheart, Dowdy Donnelly, a waiter in the same place, who is in love with her. Learning from another waiter in the place that Kelly is winning her attentions he hurriedly visits a saloon, and in the back room pleads with her to return to him. She agrees to do this on condition that he challenges Kelly, and if he knocks out the Knockout Man she will marry him. Donnelly is aided by Kelly's manager, who, instead of receiving a condition for his services in the champion's behalf, gets a blow on the jaw when he asks what is coming to him. He trains and schools Donnelly and when the latter has a bad attack of cold feet, owing to unfavorable reports from Kelly's gymnasium, Dugan hits upon the brilliant idea or knocking out Knockout Kelly as follows: While Donnelly is fighting Kelly, Dugan will stand in an obscure corner of the club, and shoot Kelly in the seat of his tights with an air gun. When Kelly turns to see who shot at him then Donnelly is to knock him out while his attention is distracted from the fight. The plans works out O.K. after several mishaps, in which Donnelly gets the shot instead of Kelly, and finally when Kelly is floored the cashier incensed at the frame up, exposes Dugan and Donnelly and marries Kelly, while the conspirators have to flee from the ire of the fight fans.