Blackthorn is a magical healer rotting in a warlord's dungeon, consumed by a vow of vengeance she cannot yet act upon, when a mysterious fey being offers her freedom at a price: seven years of binding service in the north, helping any who call upon her without seeking revenge on the man who destroyed her life. Accompanied by Grim—a massive, silent man she barely knows—Blackthorn travels to Dalriada, where she sets up as a wisewoman on the edge of a magical forest. Neither of them expected the mysteries that keep finding them.

Blackthorn is bitter, brilliant, and wounded to her core—a woman who chose to survive when she could not yet fight, and who finds purpose in the very service she resents. Grim is her counterpoint: gentle where she is sharp, steady where she is volatile, carrying his own enormous pain in silence. Their dynamic is the heart of the series.

Across three books, Blackthorn and Grim untangle ancient curses, protect the innocent, and resist the quiet bond growing between them—all while Blackthorn's enemy draws closer and her vow of service strains against her burning need for justice. Juliet Marillier weaves Celtic mythology, folk mystery, and tender character study into a series that rewards patient readers with one of fantasy's great slow-burn relationships.