Let me start by saying that Penric's Demon is set in the universe where one of my all-time favourite fantasy books (Paladin of Souls) is also set, though a hundred or so years earlier, so this novella was never going to be a hard sell for me.
For anyone who doesn't know this universe, the main premise you need to get your head around is that there are basically five gods who interact quite heavily with human beings and this has a massive impact on day-to-day life. As is the case with the trilogy, the main god involved in the plot of Penric's Demon is the Bastard, who pretty much deals with anything that has to do with disorder and is also a bit of a Trickster. In this universe, in order for someone to be a sorcerer, they have to have a Demon and this is usually fairly well-structured in terms of making sure that people who take this on have the relevant training.
Yes, this is one of those 'character X falls into a situation they have not been prepared for' books - the character in question is Penric, younger son of an impoverished noble family who we first meet when he's on his way to be betrothed to the daughter of a cheese merchant. His journey coincides with that of Divine Ruchia, who has suffered a heart attack, and who also just happens to be a sorceress. When Ruchia dies, the Demon which lives within her transfers to Penric, who then ends up on quite a different journey than the one he was planning.
It has to be said, Penric is a little naive but generally a good sort and this shows in his interactions with others, including his Demon. In some ways, he reminds me of Maia in The Goblin Emperor, in that his positive qualities drive the plot and make its resolution possible. Anyway, I really enjoyed reading this though I would have been even happier with more plot and a complete novel! Hopefully this won't be the last time the author visits this universe, as I'm sure there are plenty more tales to tell, and I'll be happy to read every last one of them...