Against all odds, Ashleigh Griffen's favorite racehorse, Wonder, has come through training with flying colors. Now Ashleigh and Wonder's trainer, Charlie, are putting everything they have into getting Wonder ready for the biggest race of her career: The Kentucky Derby. Then disaster strikes.

Brad Townsend, the son of Wonder's owner, insists on working Wonder one icy winter day. As Ashleigh and Charlie watch in horror, Brad gallops Wonder too fast, and the filly stumbles on the frozen track, badly injuring her shoulder.

After two years of hard work, have Wonder's chances been ruined in a split second?

Read Thoroughbred and experience the love and friendship between a determined girl and a very special filly.