The Spell of Undoing — Paul Collins

Calamity has befallen the city of Quentaris! Due to a vengeful plot by warlike Tolrush (which backfires), Quentaris is uprooted -- city, cliff-face, harbour and all -- and hurled into the uncharted rift-maze. Lost and adrift in this endless labyrinth of parallel universes, encountering both friend and foe and facing unknown dangers, Quentaris must somehow forge a new identity and find its way home.