When the Gordon's neighbor Lady Faulkner discovers her racing horses are being drugged, their curiosity gets the best of them. After Dr. Gordon is attacked and Albert rescues the constable from a well, the pieces start to come together. But it's Black Beauty who delivers the decisive moment.

Dr. Gordon is arrested for a cottage burning that belonged to Mr. Skinner after he criticized it's condition. Vicky, Albert, and their friend Jill work to clear his name but need Black Beauty's help. Complicating matters is a mysterious man Duffield and a horse identical to Beauty.