Ashleigh Griffen's dream has come true. Her parents have bought their very own racehorse, which means Edgardale farm has a shot at winning the Kentucky Derby! The entire Griffen family works overtime at training Royal Renegade for his first big race. And he wins! But then something goes terribly wrong. The even-tempered stallion suddenly turns mean and starts losing races. No one can figure out why. Will Ashleigh solve the mystery before it's too late for her Derby dreams?