Cindy has trained Storm ever since he was a colt.Now he is a full-fledged racehorse and he is blindingly fast. In his three-year season at Gulfstream Park, Florida, he piles up victory after victory. Cindy is cure that Storm is on his way to becoming a champion.
When they get back to Whitebrook(there ranch), though, disaster strikes. Cindy discovers that an incureable disease has spread through the area. So the vet tests Storm and all the other horses on Whitebrook only to find that Storm tests positive, and the vet warns that if they don't put Storm down(kill Storm),he may spread the disease to all the other horses. Cindy is heartbroken(that's were the book got it's name Cindy's Heartbreak)at the thought of losing her beloved Storm. But can she risk putting her other horses in danger to save Storm's life?