I read Thud! when it was first published, and can still remember the slightly puzzling feeling of disappointment. Pratchett’s recent novels – Going Postal and Monstrous Regiment for example – had been imperious, but this was a slight mis-fire. Or so I remembered. But memory can be misleading – would the novel have the same impact some fifteen years on?

Yes and no. On the one hand this is a Watch novel, featuring Sam Vimes and his team. It’s also in many ways an exceptionally well-constructed detective novel, albeit in a fantasy setting featuring dwarves, trolls, vampires and werewolves. Some critics have found the pastiche of The Da Vinci Code a little heavy-handed, but I thought the references were just right, not such that you knew what was coming next, but that you could see the parallels. So what’s not to like? I think partly the problem is that Pratchett had set such high standards in his recent work that something that doesn’t quite reach those levels is likely to disappoint. Because I don’t think Thud! ever quite comes to the boil; there is a lot of time spent setting up a climax that never really arrives.

The plot is more complex than most Discworld stories. A dwarf, Grag Hamcrusher, has been murdered, and a troll is the prime suspect. The radicalisation of the dwarven community that had been suggested in earlier novels has accelerated, and all-out conflict with their eternal enemies, the trolls is imminent. Hamcrusher was a deep-downer, someone who believes dwarves should remain underground and avoid contact with other races. His murder couldn’t come at a worse time for Sam Vimes and the Watch, because it stokes tensions between Ankh-Morpork’s troll and dwarf communities just as the anniversary of the Battle Of Koom Valley approaches. This battle (or series of battles) happened centuries ago, but is still a cause for resentment between trolls and dwarfs, who now come into close daily contact on the streets of Ankh-Morpork. At first it looks like the deep-downers will obstruct the Watch’s enquiries, preferring to deal with it themselves, but Vimes persuades them to accept an investigation by Captain Carrot, human by birth, dwarf by upbringing. Carrot is assisted by the new recruit, Lance-Constable Sally von Humpeding, the Watch’s first vampire, as well as his werewolf partner, Sergeant Angua. Vampires and werewolves are traditionally the fiercest of rivals leading to tension between Angua and Sally.

Elsewhere in the city a painting has been stolen. This is a job for Corporal Nobbs and Sergeant Colon, Ankh-Morpork’s finest. The fifty-foot painting, The Battle of Koom Valley by Methodia Rascal, is believed to hold a clue to the treasure of Koom Valley. (Because as well as being the site of many battles between trolls and dwarves, Koom Valley also hides some lost treasure). Vetinari could not have chosen a worse time to send an auditor, A.E. Pessimal, into the Watch. This is one of the novel’s misfires – Vetenari has shown every evidence previously of having confidence in Vimes and being willing to let him get on with his job, but now with Vimes at the head of a massively expanded Watch he sends in a book-keeper? Vetenari would already know everything he needed to know about the Watch and sending in an auditor would be an admission of failure. Vimes would almost certainly have sent him packing instead of, as he does, meekly accepting his presence. The same applies for Vetenari and Vimes’s acceptance of someone who is obviously a spy into the Watch – they just wouldn’t have done that in previous novels.

And so it goes on – people not behaving quite like the characters Pratchett has spent years developing. Carrot goes missing from the text, with his investigation largely happening off-screen. Angua behaves like a spoiled child and Vimes manages to completely ignore a summons from Vetenari, something that would have been unthinkable previously. There is a supernatural element to the novel – the Summoning Dark – which has strong echoes of the hiver in A Hat Full of Sky but which here seemed superfluous. The novel’s finale falls flat – the happy ever after resolution manages to be both predictable and unconvincing.

A mis-firing Pratchett is still head and shoulders above most novelists, and there is plenty to enjoy here. Sam Vimes’s character development is almost complete – he is now father to young Sam and takes his story-reading duties just a little too seriously. Minor characters, such as Willikins, Sam’s dead-pan butler, are a joy (“‘My gods, man, you’re covered in blood!’ Sybil burst out. ‘Yes, your ladyship,’ said Willikins smoothly.  ‘May I say in mitigation that it is not, in fact, mine.’) and A E Pessimal the auditor turned blood-thirsty Watch recruit shows promise. Other more familiar characters seem to be on auto-pilot or go missing in action completely, and Tawnee, Nobby’s pole-dancing girlfriend is a mis-judged caricature.

Thud! is much loved by the vast majority of Discworld fans. It’s the only book I have ever seen with 0% one star ratings on both Goodreads and Amazon, which shows how well it is regarded. So who knows, I am probably missing some of the wonders of this novel, one of which is jokes like this variation on the Monty Python “What have the Romans ever given us?” sketch:

“War, Nobby. Huh! What is it good for?”
“Dunno, Sarge. Freeing slaves, maybe?”
“Absol-well okay.”
“Defending yourself against a totalitarian aggressor?”
“All right, I’ll grant you that, but-“
“Saving civilization from a horde of-“
“It doesn’t do any good in the long run is what I’m saying Nobby, if you’d listen for five seconds together.”