Howl's Moving Castle

Sophie, the eldest of three daughters, has dutifully resigned herself to a dull life running a hat shop.
But when she runs afoul of the evil magic of the powerful and testy Witch of the Waste, her life becomes very interesting indeed. The Witch's curse turns Sophie from a young woman into an old one.
In shock and desperation, Sophie finagles herself a job as housekeeper in the Moving Castle belonging to Howl, a wizard with a (perhaps undeserved) unsavory reputation, in hopes that either Howl or his fire demon Calcifer prove capable of removing the spell.
Acclaimed Japanese director Hayao Miyazaki based a 2004 animated film on this book.