My Old Kentucky Home (1922)

After serving time in Sing Sing, for which he was unjustly sentenced, and encouraged by two "sharpers," Richard Goodloe returns to the home of his wealthy southern mother in dread fear that she and Virginia Sanders should learn of his prison record--a fear which is constantly nurtured by his rival, Con Arnold. Richard enlists the aid of his two friends to help Dixie, his mother's horse, win the Kentucky Derby. Realizing Dixie's inability to do so, they substitute Calamity Jane's Lightnin', which does win the race. Arnold exposes the substitution and Richard's past, but his triumph is interrupted by a detective, who arrests Arnold for past crimes.