Last time round (https://www.goodreads.com/review/show/5181627876) I just had to herald a really strong start to a series of juvenile crime stories. Then it was a PE teacher found dead, which inspired our lead characters to club together and solve the case. Here you just think something else is happening of a dubious kind at the school, when talk of some mysterious trade is overheard, when something else really startling turns up – proof that in no way does this ever-surprising series dumb or water down the nastiness just because it's for the under-twelves.

That's not to say it's full of gore, guts and grue, but that it's full of what will unsettle, and go against the cheesy easy cosy crime of much that this age bracket gets left with. It involves another dead person, and a most surprising confession from someone we didn't expect to feature here at all. For our heroine's erstwhile parent has come back into the fold – meaning Lydia Strong is really going to find her attention split – the issue of the reunion with her family, the shenanigans at school and the murder – and the unexpected connection that has with the first on that list.

This again isn't perfect – the heroine remains very up herself and still doesn't get the demanded comedy out of her ego – but for me the merits are still easily seen. It's a distinctive read, with realistic children, forced to want to be super-heroes and yet to admit their powers aren't all that. They certainly hesitate – or least the lads do, perhaps not Lydia – meaning they don't charge head-first into stupid events like their kin in other crime books. But they still have enough agency to prove their company well worthwhile. And indeed it will be a sore disappointment if I don't get to see the trilogy closer – this is a strong four stars and to see it all wrapped up in future will be something to relish.