Howl's Moving Castle is another world in which magic is an only slightly uncanny part of everyday life. In this case, the land of Ingary is meant to resemble a world in which fairy tales like those of the Brothers Grimm are real. The technological level and character of society feels like the eighteenth or early nineteenth century, the time when such stories were first seriously collected. Sophie, the eldest daughter of a hat-maker, is convinced that she is destined for an uninteresting life (it is the youngest child that succeeds in fairy tales), resigned to working for ever in the hat shop. All this changes when a witch whose emnity she has somehow attracted turns her into an old woman. Unable to bear the thought of her family seeing her like this she secretly leaves home and sets out across the moors above the town.
There she ends up seeking shelter in the wandering castle of the wizard Howl, feared as a monster who eats girls' hearts. Howl turns out to be not quite as bad as his reputation, but with enough bad qualities (vain, irresponsible, evasive) to irritate Sophie. Sophie's transformation, though, has given her an opportunity to change her own character. Previously she had defined herself as a dull, shy and unconfident person. Now as an old women she feels quite ready to boss people around and is generally more free of the anxiety she had as a young woman.
The story is an adventure story of course: Sophie is trying to break Howl's contract with his fire demon Calcifer, who in exchange will restore her youth; Howl is trying to escape from the Witch of the Waste, the same witch who turned Sophie into an old woman. But it is a very domestic adventure: Sophie finds a new family in Howl's castle and secretly falls in love with Howl.
Miyazaki's version of the story departs from the original far more than The Borrowers or Kiki's Delivery Service. Like most adaptations, it starts close to the original, then gradually diverges. The major change of setting is that the feel of society is now somewhere around 1900. Instead of "what the fairy tale world would be like if it were a real working society" we have "what the Edwardian age would be like if it had magic". For the most part this means only the trivial loss of some whimsical humour, but it also means that we no longer have the idea that Sophie is trying to live down to her archetype, as she sees it. The change of setting is not so great that the film cannot take over most of what is in the book, even in odd little details. For instance:
At that moment two empty cake racks were pulled away at the other end of the room, and an apprentice stuck his head through from the back somewhere. "Thought I heard your voice, Lettie," he said, grinning in the most friendly and flirtatious way.The other major innovation is that the country is at war in the film. In the book there are a couple of points where we see that Howl's services are wanted by the kingdom for essentially military purposes; but this is just background, and there is no war actually taking place. When the film was being prepared, the Iraq War started, and it unsurprisingly took a grip on Miyazaki's imagination. While the book Howl is avoiding serving the king chiefly for self preservation, film Howl becomes an antiwar figure. This, combined with the aesthetic of Japanese animation, seriously changes his character. Book Howl is selfish and self dramatising and tries to push those in his household around (generally without much success). Film Howl has excessively gentle looks, voice and manners.
The two stories really go there separate ways once the war becomes a major element of the plot, crossing each other's path intermittently for the rest of the film. Occasionally whole scenes are taken over (the transfer of the castle to a new home, for instance), but more often little details are used in a new way. Making room for the war, most of the subplots are stripped out. Losing the subplots (mostly involving Sophie's sisters) is probably not such a bad thing. One gets the feeling that Jones was very fond of how the parts of a complicated plot worked together and enjoyed seeing all the elements working out more than most readers. None of these subplots are bad or unenjoyable, but their real value is more in showing us Sophie's character and its development, which Miyazaki handles in a different way. We also lose Howl's background in Wales. Probably many readers will not miss it. In the book it really only throws a little more light on Howl, as someone fleeing a dull, unhappy background who has decided to invent himself as a new character.
In contrast to the book, the film becomes less complex towards the end. That includes one horrible over-simplification in the final scene, where the war is done away with in a couple of sentences; but on the whole the increasing simplicity is a gain, especially since the war plot never seemed properly integrated. As often, a key scene is something not in the original, but takes its inspiration from a different episode. In the middle of the book, Sophie and Howl's apprentice Michael (a teenager in the book) are trying to catch a falling star in the marshes outside town. The episode starts as comedy, then takes a different tack.
Michael was stalking the star with soft steps, both arms out to catch it. Sophie could see him outlined against the star's light. The star was drifting level with Michael's hands and only a step or so beyond. It was looking back at him nervously. How odd! Sophie thought. It was made of light. It lit up a white ring of grass and reeds and black pools round Michael, and yet it had big, anxious eyes peering backward at Michael, and a small, pointed face. ...
Sophie tried to say to Michael, Do stop, it's terrified! But she had no breath left to speak with.
"I only want to catch you," Michael explained. "I won't hurt you."
"No! No!" the star crackled desperately. "That's wrong! I'm supposed to die!"
"But I could save you if you'd let me catch you," Michael told it gently.
"No!" cried the star. "I'd rather die!" It dived away from Michael's fingers. Michael plunged for it, but it was too quick for him. It swooped for the nearest marsh pool, and the black water leaped into a blaze of whiteness for just an instant. Then there was a small dying sizzle. When Sophie hobbled over, Michael was standing watching the last light fade out of a little round lump under the dark water.
"That was sad," Sophie said.