Jerry, a ne'er-do-well, after losing his latest job, drifts into a cabaret and meets Laura White, a dancer. Hubert Strief, a crooked fight promoter, who also desires Laura, has one of his thugs work over Jerry; as a result the boy shamefully reviews his life--his laziness and neglect of his mother. He obtains a job as helper in Montana Mack's gymnasium and after lengthy training proves himself a skillful fighter; but through the treachery of Strief, he is knocked out and sent to a sanitarium. Regaining his memory, he escapes and thrashes the villains, who are holding Laura against her will. In the climactic fight, Jerry wins the championship and the love of the girl.