Secrets of the Opal Sea (Paperback) (ISBN-13: 9780578310060)

Spirits of Cape Hatteras Island - Secrets of the Opal Sea:

Underneath Cape Hatteras Island lies a secret that has been hidden since the time of Atlantis. After a heavy sound-tide flood three cousins are walking by the Old Opal Pond; Ellie let's out a yelp and disappears from sight. Luke and Blake rush to where Ellie was last seen and discover she has fallen down a hole. After clambering down the hole the trio will see things like no other. Along with the many wonders awaiting them so to does an old enemy.