Legend has it that the giant Balor of the Evil Eye will return bent on revenge to destroy the remote island of Inish Álainn in his search for a magical stone. The only ones who can stop him are the mysterious ‘Chingles from the East’.

But what does this have to do with Cassie, Thomas and Nancy who are spending their summer holiday on the island with their Uncle Jarlath?

Before they are even off the ferry, the children are plunged into an adventure where they encounter mischievous and dangerous creatures from Irish myth, learn of the mysterious powers of shapeshifting and meet the magical trees of the Sacred Grove.