Dark Lord of Derkholm (Derkholm Series #1)

Mr. Chesney operates Pilgrim Parties, a tour group that takes paying participants into an outer realm where the inhabitants play frightening and foreboding roles. The time has come to end the staged madness...but can it really be stopped? Diana Wynne Jones serves up twists and turns, introduces Querida, Derk, Blade, and Shona and a remarkable cast of wizards, soldiers, kings, dragons, and griffins, and mixes in a lively dash of humor.