The Sea Pony (Piper Green and the Fairy Tree, Bk. 3)

When Piper Green discovers a funny-looking whistle in the Fairy Tree, she is stumped. Piper doesn't want a whistle . . . she wants a pony, like the one that just arrived on the island ferry. Then a trip with her dad to check the family's lobster trap attracts an unusual friend. Could the Fairy Tree be working its magic after all?