Fantasy intertwines with action and adventure to create a poignant, unforgettable tale of a knight determined to do whatever it takes to protect his queen. Exiled from the Winter Court, Prince Ash embarks on his arduous quest of honoring his vow to forever stand by Meghan Chase’s side. Accompanied by his infuriating arch-nemesis Puck and the lofty cait sith Grimalkin, Ash seeks the one thing that will allow him to set foot in the Iron Realm and become Meghan's knight without dying: a soul.

The impossible trials Ash endures, along with the haunting revelations he faces, shape his evolution from a callous Unseelie to a sentient fey capable of feeling guilt, remorse, and love. Shocking discoveries, devastating sacrifices, and painful memories finally lead Ash to question his clashing motives: If he wasn’t irrevocably bound to his oath to protect Meghan, would he truly want a soul? Does he even deserve to become human, after he left behind an endless trail of destroyed lives as a young and arrogant Unseelie?

In the enthralling conclusion to the Iron Fey series, Julie Kagawa weaves a hauntingly intricate tale of humanity, love, sacrifice, regret, and friendship.