Where Is Winky's Horse? (2007)

Winky is the happiest girl in the world because she gets to take care of Santa's horse, Amerigo; only it turns out not to be as easy as she thought it would be. Winky learns to groom for the horse from her uncle and aunty, but she is not allowed to ride Amerigo until she is much bigger. Winky finds that hard to accept. One day, when nobody is around, Winky decides to take a ride. But something terrible happens. Amerigo escapes. Winky has to find him back before Santa returns.