Little Joyce Fairfax loves her thoroughbred colt “Satan.” When financial difficulties force her young, widowed mother to sell her estranged grandfather, Judge Boyce, who had disapproved of her mother’s choice of husband, buys him secretly. When the judge also suffers reverses, he enters Satan in the Dixie Stakes where the unscrupulous Silas Morgan tries trickery to prevent the colt from running. He almost succeeds until a mysterious rider comes to the barrier, and rides Satan to victory. When Mrs. Fairfax hastens to the paddock, she finds Joyce very muddy and soiled in her jockey colors, just then Judge Boyce arrives, and the trio are reunited.

The day after the funeral of their beloved daughter, Mrs. Mason unexpectedly meets young orphan Joyce and is struck by her resemblance to her lost child. She and Mr. Mason adopt her and for a while all is well until Joyce begins to suspect Jenks the new butler. Her instinct proves correct: Jenks is the tool of Jim Vaughn, notorious leader of a burglary ring. One night while Mr. Mason is out trying to resolve some business difficulties, Jim Vaughn breaks into the house. Joyce, awakened, hears him removing valuables, aided by Jenks. Desperate, she grasps her foster father's revolver holding them at bay while phoning Mason. Arriving with the police, Vaughn is captured. Joyce is presented the $5,000 reward which she turns over to Mason, solving his problems.