After a strange encounter at a science competition, Wren Matthews discovers a secret magical order known as the Fiddlers, and must learn to use the power of stardust to save them, herself, and the world from the return of a sinister enemy.

There is a crisis in the Starlight Kingdom, one of the fantasy worlds: its stars, powered by a special kind of stardust, are fading and may soon go out forever, leaving the Kingdom in darkness--so the Thea sisters and Will Mystery set out for Brightstar Castle to discover what is wrong, but first they must overcome the obstacles and challenges that the fairies are placing in their way.