Horses of the Dawn, book 3 : Wild BloodKathryn Lasky2016

Destiny Can't Be Bridled
After adopting an orphan human boy, the First Herd is finally ready to make the treacherous journey across the mountains to find the Sweet Grass that promises survival. But when their leader, Estrella, is captured by cruel men, it delivers a blow to the very heart of the herd. If the horses turn back, they'll never make it across the mountains before winter. But if they leave Estrella in captivity, the wild-born filly will surely perish. This conclusion to Kathryn Lasky's Horses of the Dawn trilogy will make your heart beat to the rhythm of thundering hooves, leaving you breathless as you join the herd's final fight for freedom.