Because boxing is a considered an illegal and disreputable enterprise in 1880's San Francisco, wealthy and influential members of the prestigious Olympic Club vow to make the sport a "gentlemanly" one. They sponsor a brash, extroverted young bank clerk named Jim Corbett, who quickly becomes an accomplished fighter under the new Marquis of Queensbury Rules. Despite his success, the young Irish-American's social pretensions and boastful manner soon estrange him from his benefactors, who plot to give their conceited former protege a well-deserved comeuppance. Despite this, his dazzlingly innovative footwork helps him to beat a succession of bigger and stronger men, and he finally finds himself fighting for the world's championship against his childhood idol, John L. Sullivan.