by Child of the King
Coyote Summer is a movie about a 15-year old girl, whose name is Cassie and a horse named Kia (it sounds like ky-ya). Cassie lives in the city with her single mom.
When her mom's book is published, her mom has to go on a business trip to England. Cassie's mom decides that Cassie is too rebellious and disobedient to come all the way to England so she takes her to Aunt Maggie's ranch in the country. I'm not exactly sure where the ranch is, state-wise, but there are cougars and canyons so that should give you a pretty good idea. Anyway Cassie gets there and meets Rafe,an experienced ranch hand, and Kia, a beautiful, half wild, thoroughbred horse.
While there, Cassie and Rafe find out that Snapper, a horse trainer is drugging the horse as part of a plan to pay off a debt. They work hard to find out exactly what's going on. They discover that Snapper owes a huge debt to a man named Mr. Wells and that Snapper had been drugging Kia, so that Cassie's Uncle would think the horse was hopelessly wild, and was going to convince him to have the horse put down, and, once the horse was thought to be dead Snapper would steal him and give him to Mr. Wells to pay off the debt.
Cassie and Rafe decide to steal the horse themselves and train him, to show everyone that he isn't wild, and enter him in a race. They train Kia, but I won't tell you the ending. This movie is so not unrealistic like so many horse movies are.