The plot - or at least the mechanics that set the plot in motion - could be straight out of a horror film. 10-year-old Chihiro's parents make a wrong turn en route to their new home and end up in a strange deserted township. Victims of their own greed, a curse befalls her parents. Then darkness falls and insubstantial, ghost-like shapes appear in the streets. Chihiro flees. Sseeking refuge at a huge old bathhouse, she discovers that yet more spirits, some benign and some quite definitely malevolent, are waiting ... and that her destiny is inextricably bound up with theirs.
The visual style is that of an opulent fantasy, sometimes creepy, sometimes delightful.
The film itself is quite simply a love story. In the most explicit (and superficial) sense, it's a love story between Chihiro (or Sen as she becomes known, having been tricked into forfeiting her name) and Haku, half youth half dragon, the unwitting apprentice to despicable witch Yubaba. Like Sen/Chihiro, his true name has also been stolen.
It's a love story about the cameraderie of friendship. Chihiro's parents are self-centred and foolish. Nonetheless, her adventures in the spirit world are motivated by a desire to free them from Yubaba's curse; and during these adventures she benefits from the support of a makeshift family of friends: a multi-limbed old man in charge of heating the bathhouse who commands a fur-ball army of sprites lathered in coal dust to keep the furnace stoked; an older girl slaving away as a cleaner who takes her under her wing; a river god bloated with a human waste pumped into his realm whom Sen cleanses; and a mysterious spirit called No Face whose personality reconfigures according to the characters he meets. Faced with the greedier denizens of the bathhouse, No Face becomes ravenous, rapacious and repellent. In Sen/Chihiro's company, he is calm and accommodating.
Most of all, though, 'Spirited Away' is a love story about the power of imagination. Chihiro's parents are scornful of the world they find themselves in, take advantage of what's on offer, and pay the price. Chihiro, though initially scared, integrates with her new surroundings and finally, as Sen, embraces them, particularly in her alliance with Yubaba's considerably more humane sister Zeniba.
Miyazaki's realisation of the spirit world, of its infrastructure, of the trompe-l'oeil architecture of the bathhouse, is breathtaking. He creates a world as believable as it is fantastical, a world his characters live in, rather than just a backdrop against which a story takes place. A world with structure and protocols and systems of transport.