Eighteen-year-old Liobhan is a powerful singer and an expert whistle player. Her brother has a voice to melt the hardest heart, and is a rare talent on the harp. They are both training for the elite warrior band on Swan Island when they are asked to join a mission that requires posing as travelling minstrels.

Their task is to find and retrieve a precious harp, an ancient symbol of kingship, which has mysteriously vanished. If the instrument is not played at the upcoming coronation, the candidate will not be accepted. Faced with plotting courtiers, secretive druids, an insightful storyteller and a boorish Crown Prince, Liobhan soon realises an Otherworld power may be meddling in the affairs of the kingdom. When ambition clashes with conscience, Liobhan must make a bold decision and a heartbreaking choice...