Howl's Moving Castle by Diana Wynne Jones
Howl's Moving Castle, by Diana Wynne Jones, starts off with a young girl trying to keep life interesting at her a dead-end job at the hat shop. So Sophie talked to the hats. No, they didn't answer her, but she talked to them just the same. "You have a heart of gold and someone in a high position will see it and fall in love you," she told one. Soon enough a plain-looking lass bought the plain bonnet and sailed off with the heart of the Count of Catterack.
"You are young as a spring leaf!" she told a caterpillar-green hat. The mayor's wife had to have that one, as did many other important town ladies. Business was good, so good that Sophie hardly had time to do anything for herself. She was working as her stepmother's unpaid apprentice. Not a penny of the money did she see, and soon enough she became pale with exhaustion. Making hats could be tiring work.
It wasn't her stepmother's fault. No, certainly not! After her husband's death, Fanny had to cope with the expense of three girls. Surely, the best way was for them to find their own fortunes. All three were pretty, but Lettie was the beauty, so she's off to apprentice in a pie shoppe, the sooner to catch a husband. Baby Martha, Fanny's own daughter, would be sent to study and live with wealthy, wise women. That left Sophie to help her stepmother with the millinery shop. Ribbons, soft fabrics, flowers, and wax fruit, that was her lot in the work shed.
Yes, she'd inherit the shop one faraway day, but she had to admit that she found the work dull as well as tiring. She didn't meet anyone, and the workers were never exactly friendly. She found herself fading into the woodwork and wasn't entirely surprised when a handsome rogue in bright silks teased her for being a little, gray mouse. When her sister clues her in to her stepmother's exciting lifestyle at her expense, well, it's enough to make even a quiet, elder child stand up for her self.
All she meant to do was ask for a wage, but fate intervened in the form of a real Witch of a customer. In the blink of an eye, Sophia is cursed, ensorcelled, and transformed into a hideous creature who must find a way to reverse the spell before she dies of its effects.
Her painful steps lead her to Howl's Moving Castle, the smoking, black structure which appeared one day in the hills above the town. They say that wicked Sorcerer Howl devours maidens' hearts, but Sophie's luck has been so bad she's willing to take that chance. This book is also available on audio and on film.