I don't remember plots very well, which has given me an odd relationship with detective stories. I read most of the Morse books, until the worsening fonzification of Morse bored me to giving up, and then I read most of the Dalziel and Pascoe books, until the overhanging literariness of the whole enterprise got to be more than I could bear. I didn't read them because I wanted to know whodunnit; I read them because I was checking in to see how everyone was getting on down at the Oxford nick or the Yorkshire fuzzery. The only set of detective novels where I'd have any chance at all of remembering the plots is the Yellowthread Street books, because the plots of those books were so wilfully outrageous you can't help remembering them. And even then I wasn't that bothered about whodunnit; I was tuning in to see how Spencer and Auden would trip each other up, and what mad combination of circumstances would bury the much put-upon Christopher O'Yee under a pile of his own neuroses.
Which is all by way of saying that I read Moon Over Soho to find out what DC Grant and DI Nightingale had been getting up to rather than to steep myself in a mystery. Which is probably just as well, since the principal appeal of the books is the characters themselves rather than the plots, which are unlikely to rise Agatha Christie from her unquiet grave; the principal piece of suspense in Moon Over Soho for the reader is wondering how much longer it's going to take Grant to figure out that he's banging the villain. From a purely technical point of view, Aaronovitch is doing a good job of depicting someone who hasn't figured out what's going on, if it weren't for the fact that it's first person narrative explicitly written after the fact, and even if Grant doesn't realise how dumb he's being at the time, he'd have a crushing sense of it once he sat down to write about it…..
So the actual plot for the book isn't that impressive, but the larger plot of the series is banging away on all cylinders. Nightingale's still something of a mystery, as he should be, and the messy things from the first book are messy now; poor old PC May is still massively messed up, and Nightingale is on sick leave for most of the action since being shot almost dead is not something you just walk off.
Things which are a bit worrying; DC Grant is turning into Captain Kirk or James Bond, forever embroiled in romances which end up with the damsel getting briskly written out of the action somehow. Magical London might be getting a bit Harry Potter-ish, what with poor old PC May going all Hermione  on us in the closing pages; this, I do not like. Magic's not magical if everyone's got it, for a start, but more importantly, May was more interesting as a character who wasn't magical. There should not be one for everyone in the audience. And of course, it's always worrying that there seems to be some over-arching big bad staying one step ahead of the action; Hermione is bad enough, but Voldemort too?
Yet, it's all going pretty well despite those quibbles. Grant's an engaging narrator in a world full of rounded enough characters. I continue to enjoy the constant asides about how things work, and I like the notion of his magical world where no-one really knows how it's all supposed to work and hardly anyone even cares. And I'm interested, still, in what comes next. Aaronovitch is doing that right. For the moment.
 Full disclosure; I haven't read Harry Potter, but since I live in the world, I can't help knowing about it.