Trudy Erskine has never felt like she belongs anywhere except Glencarragh. Spending summers on Glencarragh with her Aunt Calla she does the very thing her aunt warned her against - she makes a bargain with a faery. Years later, Trudy begins to feel settled when she takes a job on the island as a teaching assistant. She loves her work and has found great friendship in Frances and Cliona who accept her strange, daydreaming ways. When Trudy stumbles across a selkie boy she discovers all of her daydreams have been real - she has the ability to travel in between Faery and the mortal realm. The oath she made years ago is being called in by none other than Skelly, an exiled lord of the sea. What Skelly wants Trudy to do would mean sacrificing her life as she knows it. But, when you make a promise to a faery, do you have any choice but follow it? In the exciting conclusion of the Sea Glass Trilogy, return to Glencarragh - to old friends and new - for a tale of hope and magic, where one woman's desire to escape her worries takes an unexpected turn.