Catherine in jumping in an adjoining field when Napoleon breaks out of his pasture, only to be injured by Catherine's horse. Everybody goes to Napoleon's aid, but when they finally get him back into his stall and the vet is called, the Black goes crazy and stands guard over the little horse. He lets Alec into the barn, and after watching him closely for the night, Napoleon recovers.
Alec participates in a commercial commemorating the last pony express rider. While on route, Alec gets lost and comes upon a Native American named Hank who reveals the truth about who the last pony express rider really was.
An underhanded paparazzo, injured after provoking The Black, persuades a judge that the horse is a menace. When Alec learns of plans to put The Black down, he runs away on The Black and a manhunt ensues.
Alec and Henry visit an old friend of Henry's who has a troublesome nephew named Dennis. When Dennis sets the Black off, it sets into motion a whole series of events that endanger the lives of both him and Alec's.