Abdullah lives in a traditional fantasy Middle East, dreaming of marrying a princess and going on adventures rather than selling carpets in a market stall. When a mysterious man sells him a magic carpet, Abdullah's dreams start coming true; the carpet takes him to meet Flower-in-the-Night, a beautiful princess sequestered in her father's castle. But when an evil djinn makes off with Flower-in-the-Night, Abdullah is plunged into the darker side of his fantasies as he strives to find and rescue her and all the other princesses the djinn has stolen. 
 As a sequel, this idea is brilliant; rather than taking on the same characters from Howl's Moving Castle immediately and showing us what they're doing, Jones introduces an entirely new character from a different part of the world and places him in the middle of a snafu the heroes from the first book have found themselves in. That we don't even know said heroes are involved until the last few chapters is a stroke of genius, and seriously adds to the book's re-readabilty value. 
 The characters are, as usual, brilliantly written; my favorite was Flower-in-the-Night who makes up for her enforced ignorance by reading and learning as much as she can as quickly as she can. She goes from a young woman who thinks all men look like her father (and thus Abdullah is a woman) to a woman who can stand up to and fool a djinn in order to help secure her freedom and that of all the other princesses. 
 Yet another quality offering from Diana Wynne Jones, whose books continue to make me sad I didn't discover them when I was younger.