Summer is winding down for Kate and her friends when a surprise visitor appears at her family's stable--a beautiful bay horse wearing a halter and a bad attitude. Dubbing the horse "Rebel", the friends set out to find the horse's owner. Where did he come from, and why are horses all over the area disappearing from their pastures and paddocks? It's a mystery that even the sheriff can't figure out, so Kate decides to head up the investigation. When Kate's autistic brother, Pete, develops a strong connection to the new arrival, Kate wonders--did God bring Rebel to them for a bigger purpose?