The last days of the edge of the world

Six of the world's seven edges have been rounded out and the last one, edging a thin sliver of land where magic still survives, is in a parlous state. No longer able to remember the future, the last enchanter, Sirion Hilversun, knows that is about to die, and is anxious for the fate of his young daughter Helen, when a letter arrives from the neighboring unmagical kingdom of Caramorn, asking for his daughter's hand in marriage. Helen does not know that the offer is a desperate move on the part of the king of a bankrupt kingdom, but she hates the idea anyway. Unfortunately her cunning plan to avoid the marriage without disappointing her father too much goes badly awry when it volves her and Ewan, the boy hired to catalogue Caramorn's palace library, in a spell that has been gathering power for hundreds of years. If she and Ewan can complete the spell, the last of the world's edges should be neatly disenchanted and tidied away -- but can the human pawns necessary to complete it survive the obliteration of the magic lands?