May and her family are spending two spring weeks in England. Her big sisters, Dottie and Ellie, keep teasing May about the piskies--spirits who hide in the nooks and crannies of Cornwall and come out to make mischief. The windy, wet region has something wonderful, too--wild ponies. May has never seen one, and she can't wait. Then, when the three girls venture out one night, Ellie falls and twists her ankle. She can't walk. Now May must ride a strange pony through pisky territory to get help!