The Island Stallion's Fury — Walter Farley

Only Steve Duncan and his friend Pitch know of the valley hidden behind the high cliffs of the remote Caribbean Azul Island. And only the two of them know of the beautiful, purebred horses that live there, under the watchful eye of the great red stallion, Flame. But when Pitch's half-brother Tom learns of this lost paradise, he will stop at nothing to make it his own, even if he has to destroy it.