In any long running series, especially where the author produces books with the regularity that Terry Pratchett achieved, one looks out for repetition – recycled material, sometimes ironically self-referential, sometimes disguised. So when I tell you that Hogfather features Death leaving his day job and assuming the role of the missing, presumed dead Hogfather, the Father Christmas of Discworld, it will ring some bells. Didn’t that happen before, in Reaper Man and before that in Mort? (It did). To be fair, that’s a minor quibble, because as I am sure I have said before, with Pratchett it is never about the plot.

Here, Death is not taking a holiday, but covering for the Hogfather, who despite being the titled character makes only the briefest of appearances. Death is driven to do this on the basis that the Hogfather is responsible for the sun rising each morning, and for this to happen children have to believe in him. It’s not as awkward and contrived as it sounds.

Having failed to force Death to retire in Reaper Man, the grim Auditors of Reality, “celestial bureaucrats”, hire an assassin from the Assassin’s Guild to kill the Hogfather, symbol of all that is creative and joyful in the Discworld. A particularly psychopathic assassin, Mr. Teatime, is assigned the job.

“Mister Teatime had a truly brilliant mind, but it was brilliant like a fractured mirror, all marvellous facets and rainbows but, ultimately, also something that was broken.”

He recruits a gang of Ankh-Morpork’s more unpleasant thugs (and that’s saying something) to capture the Tooth Fairy’s kingdom, steal all the collected teeth, and use them to control the children of Discworld, commanding them to no longer believe in the Hogfather. Again, still not awkward, contrived, or even twee. Honestly. Pratchett gets away with this because the narrative doesn’t give us this summary – the reader is left to work most of this out themselves, and the immediacy of the action – we are just shown what is happening in the moment – is realistically portrayed. There’s a darker element to the novel as well – when Mr Teatime kills people they stay killed.

Death, becoming aware (somehow) of the Hogfather’s absence, decides to fill in for him. Along the way he visits his granddaughter, Susan Sto Helit, tricking her into investigating the Hogfather’s disappearance. This is not the first time Susan has been called upon to help Death, although at least this time she is not collecting souls for him. She tracks a missing tooth fairy to the Hogfather’s Castle of Bones, on the way meeting Bilious, the “Oh God” of hangovers (one of Pratchett’s better throw away jokes). I am not going to spoil for you what happens there, but I bet you can work it out!

As well as spending time with Death and his assistants the Death of Rats and the ever-hopeful raven, exploring the Hogswatchnight traditions of Discworld and gently satirising the commercialism of Christmas along the way, we also follow the wizards of the Unseen University as they get ready for their great midnight feast, at the same time try to understand why new minor magical creatures keep popping into existence, such as the hair-loss fairy:

“No sense in being bashful about goin’ bald,” said Ridcully evenly. “Anyway, you know what they say about bald men, Dean.”

“Yes, they say, ‘Look at him, he’s got no hair,’” said the Lecturer in Recent Runes.

Susan and the Oh God try to work out what has happened to the missing tooth fairy, and why Death is substituting for the Hogfather, while Mr Teatime and his gang ransack the Tower of Bones. It’s all handled flawlessly by Pratchett, and the reader happily suspends disbelief for the duration, not least because all the characters themselves are constantly telling one another how unlikely everything is.

The Discworld version of Christmas is inevitably a much earthier version of our own Dickensian yuletide. The Hogfather’s sleigh is pulled by four fearsome wild boars, Gouger, Rooter, Tusker and Snouter. But even in Discworld traditions are being slowly sanitised. In earlier times the Hogfather gave households pork products, and naughty children a bag of bloody bones; now all the Hogfather brings is soldiers, dolls and noisy toys for that 4.30 am start.

Pratchett as ever is a great moral philosopher, with Death as his most articulate spokesperson:

“All right,” said Susan. “I’m not stupid. You’re saying humans need… fantasies to make life bearable.”

REALLY? AS IF IT WAS SOME KIND OF PINK PILL? NO. HUMANS NEED FANTASY TO BE HUMAN. TO BE THE PLACE WHERE THE FALLING ANGEL MEETS THE RISING APE.

How’s that for poetry – “where the falling angel meets the rising ape”? I rarely feel the need to justify reading what some people (entirely wrongly) consider children’s books, but here Pratchett provides the answer himself in one elegant, poetic and profound phrase.