Master of Horses — Katharine Kincaid

SHE WOULD BE TAMED BY DESIRE...
Maria Encanta was rebelling with all her tempestuous will. A virtual prisoner on her father's ranch since the death of her Native American mother, she was determined to run away and take the best horses to her mother's tribe, who still followed the buffalo on foot. For the restless beauty would rather be a thief than face the fate her father had planned for her: become the concubine of a man called Diego, Master of Horses.

OR SET FREE
Don Diego de Ibarra arrived astride a stallion, looking like a conqueror. And Maria was to be his conquest. But instead of submission he found a tantalizing defiance--and an explosive joining of two fiery souls. Now, if Maria could win Diego's help, she might deliver the steeds that are the Indians' best chance for survival. And if Diego defied his world for her love, together they could ride the very wind to ecstasy...