Yale grad Dan Brooks (Bing Crosby) is expected to marry wealthy boss J.L. Higgins' (Charles Bickford) daughter Margaret (Frances Gifford) and join the family box-making business. He is far more interested in racing a horse he owns, Broadway Bill.
Doing poorly at work, Dan and his groom Whitey (Clarence Muse) leave town to enter Bill in the Imperial Derby, but first must find money for the entry fee. He and old pal Professor Pettigrew (Raymond Walburn) each try to con the other out of a few bucks, then end up singing the Yale school song to get out of a restaurant tab they can't pay.
Maggie's younger sister Alice (Coleen Gray) is secretly in love with Dan, so she offers him some money, pawning her belongings. Whitey is beaten up trying to win some in a craps game, and Broadway Bill is carted away because Dan doesn't pay his feed bill. Dan is jailed, too.
A rich man makes a bet on 100-to-1 shot Bill, leading to false rumors that the horse is a shoo-in. The odds drop fast, but gamblers and a crooked jockey try to make sure their own favorites win the race. Broadway Bill somehow manages to win, but collapses at the finish line and must be put to sleep.
A saddened Dan takes comfort in deciding to buy and race Broadway Bill II. His enthusiasm persuades Alice and even her dad to lend Dan a hand.