A doctor is driven into an investigation of sinister goings-on at a horse race track by his mystery writer ex-wife.

Frankie Reynolds (Frankie Darro' ), youngest member of a family of jockeys, borrows $4.85 (yes, four dollars and eighty-five cents) from his sister Phyllis (Gladys Blake), who is not a jockey, to buy a crippled colt from the stables owned by Clay Harrison (Kane Richmond). He nurses the colt back to health, and in two years has one of the fastest horses in the country.