Best friends May Grover and Jasmine James each have their own pony. So does their neighbor, Joey Dutton. And when May, Jasmine, and Joey aren't riding their ponies in their backyards, they're riding them at Pony Club meetings at Pine Hollow Stables.

Then Joey's family moves away, and a new neighbor moves in. At night, lights flicker on and off inside the house, and strange noises come from the stable.

What's going on at Joey's old house? Can two pony-crazy girls find out?