The only thing twins Fran and Kiera have ever agreed on is that it would be wonderful to own a pony -- a pony they could gallop and leap over jumps.

One day their father brings them Jigsaw, a Shetland pony who needs a new family. Jigsaw is the perfect pony. He can do anything -- even fit himself into Dad's station wagon for the ride home.

But with Jigsaw comes trouble. The more Fran and Kiera like something, the harder it is for them to share. And they love Jigsaw. Worse, Jigsaw won't gallop far and he won't leap more than a couple of jumps. Is something wrong with the way the twins ride? Or is something wrong with Jigsaw?