This companion novel delves into the past of Cardan Greenbriar, the High King of Elfhame, offering readers a deeper understanding of his character and motivations. The story follows Cardan's journey into the mortal world to confront the formidable troll woman, Aslog of the West. As a part of Holly Black's popular 'Folk of the Air' series, it maintains the author's signature blend of dark fantasy, intricate world-building, and complex characters. The emotional arc explores themes of identity and the nature of power. This book is ideal for young adult readers who are already fans of the series and wish to explore Cardan's perspective further, or for those who enjoy rich, fae-centric fantasy with a touch of danger and intrigue.