In 1803, Ireland is firmly under the thumb of British rule, torn with the ongoing turmoil between Protestant and Catholic. In this fractious climate, Seamus Firnan of Donamorgh secretly leads the people of his estate in the worship of an ancient goddess, practicing rites that were in place millennia before Christianity invaded the island.

Sworn to the Goddess since his birth, Seamus is a Protector: one who guards the nearby forest, home to fairies and other magical creatures. But when Seamus is kidnapped, the fairies must look for a second Protector, one who will find Seamus and bring their unknown enemies to light.

That person is Tessa McCarthy, an untrained empath who passed through the forest twenty years earlier, when she was still a child. Tessa has struggled all her life to resist the emotions that flood her empathic mind. Now she has moved to an estate in the Donamorgh forest, where she hopes to live in isolation, and to once again meet the fairies from her childhood. But instead of the peaceful life she envisions, Tessa finds distraught fairies, a woman crying in a forbidden circle, and a mystery wrapped in magic that reaches through many generations.

If Tessa is to find her own peace, she must face the terrifying power that resides within her, and use it to help the people of Donamorgh.