Tiffany Aching has begun her apprenticeship as a witch, working for Miss Tick, who has one soul but two bodies. After a dull start to her work, they are accosted by a hiver, a formless spirit which can possess living bodies, driving them to acts of malice. Tiffany has to fight for her body and soul, but fortunately has a group of surprisingly capable allies: the diminutive, oft-drunk Nac Mac Feegle, and the formidably competent Granny Weatherwax.
A Hat Full of Sky is the thirty-second Discworld novel and the second (of an eventual five) to focus on the character of Tiffany Aching. Originally published in 2004, Terry Pratchett had decided to write a series of Discworld books aimed at younger readers. Amusingly, due to Pratchett's utter refusal to talk down to children, he doesn't entirely seem to know how to do this, so has knocked off the occasional double entendre from his writing and shaved off about 100 pages from his average page count but otherwise carried on as normal.
As a result, A Hat Full of Sky feels like vintage Pratchett, just more focused (no bad thing; some Discworld books tend to circle the drain a few times before finding their point, which is not the case here). The cast is much smaller than normal, the scope more intimate, bordering on the claustrophobic. Given the nature of the story is very internal, this feels appropriate.
The main story, ostensibly, is about Tiffany getting possessed and "turned bad," although Pratchett seems to be ahead on the curve on how this could have been tedious. Tiffany only spends a small amount of time possessed by the hiver, with most of the book revolving around events before and after. Pratchett is often less interested in the most obvious route to humour or action, and more interested in causes and results. Pratchett is also a very human writer, so here his focus is more on the impact caused by events on Tiffany's character and even feeling empathy for the hiver, the "monster" of the story.
That's not to say the book isn't funny. Pratchett's skill at wordplay and minor-but-amusing worldbuilding details (some of them drawing on real-life folklore, as the afterword attests) remains undimmed. He also spends a bit more time making the Nac Mac Feegle a deeper and more interesting culture. Them showing up drunk, head-butting a badger and yelling "crivens!" can only get you so far, so here a more thorough exploration of Rob Anybody's character and the motivations of his new queen - who finds the tribe's allegiance to Tiffany bemusing - adds more depth to a group previously only known for knockabout comedy value.
Pratchett also deploys Granny Weatherwax with restraint, though she has more page-time than in The Wee Free Men. One of Discworld's most iconic, formidable and impressive protagonists, it would be easy for Granny to take over the narrative and deal with Tiffany's problems for her in five minutes, so Pratchett is good at using her tactically during the book's finale, so as not to outshine our actual protagonist. Tiffany herself develops nicely here, the traditional "why am I not being taught actual magic on Day One of learning to be a witch?" storyline being quickly displaced by a more thoughtful, intelligent examination of responsibility, empathy and consequences.
A Hat Full of Sky (****) is Pratchett at his most focused and disciplined here, delivering a smart, tight story. It's not the most expansive Discworld story and some may prefer the more widescreen/deranged antics of, say, the City Watch in Ankh-Morpork, but it's a very solid read.
