Book 7 Fortune and the Golden Trophy by Stacy Gregg

Issie is back at Ghevalier Point and her rivalry with Natasher Tucker comes to a head as the girls compete for a new prize. Issie's chances don't look good. How can she win on new horse , Fortune, a plodding piebald? There's boy trouble too with Aidan, and an unforeseen danger that threatens the whole pony club.