From beyond the northern edge of the world, the Sunkillers (undying enemies of everything that lives and breathes and is an individual) are reaching into the sky of Laent to drain out its light and warmth. Their hope is to scrape sky, land, and sea clean of mortal life and return to where they once dwelled, before the first rising of the sun. Against them stand only the Graith of Guardians, defenders of the peaceful anarchy of the Wardlands. But the agents of the Sunkillers are abroad even in the Wardlands- plotting, betraying, murdering among the Graith.

Married now for a century, Morlock Ambrosius and AloU Oaij will take different paths to counter the threat. As AloU ferrets out the enemy within the Graith, Morlock joins forces with his sister, the formidable Ambrosia Viviana, and crosses the monster-haunted plains of the deep north to confront the Sunkillers in their own realm. Morlock and AloU think their parting is temporary, but it is final. They may or may not save the world, but they will not save each other, or themselves.