Used to being the only horse, Jet finds it difficult to accept the addition of the newest member of the family. Jealous and hurt by how the new mare is stealing the affections of his beloved owner, Isabelle, and her sister, Charlotte, he decides to run away; determined to find a place where he can be the only horse and regain the love and attention he's always had. But Jet soon begins to miss the comfortable life he's always known, and to wonder if running away was a good idea after all.