One week. That was the entire length of Pippa Evans’ teaching career at Penbryn Hall, a prestigious private school for girls. On the first day that she arrived, she recognised a figure from her past. One week later, Pippa was found, the victim of an overdose.

Going undercover as Pippa’s replacement, investigator Mallory Dawson is convinced that there is a dark undercurrent in the school. It seems there are links to the Solstice Sisterhood, a cult that believed in cleansing through punishment. The six members of the cult, apparently long since over, are all accounted for, so who is bringing the practices of the Sisterhood back? And are they willing to kill to keep their secrets?

OK, this is a worrying trend. In the last three books that I’ve read, there have been two Maths teachers. This is not a good thing.

What’s also not a good thing is that my back has been playing up over the past week or so. It’s settled down now – another ache and pain to add to my list – but it makes reading a right pain when you can’t really concentrate on a book.

Which is a real shame, as I’ve enjoyed the Mallory Dawson series to date – The Birthday Girl, The Sixth Lie and The Vanishing Act – so I wish I could have given this the attention that it clearly deserved. Other writers could take notes from Sarah – too often the middle section of a mystery novel just drags, but Sarah keeps things moving and escalating without needing to pile up the bodies. There’s an gradual build-up of menace and the ending justifies that build-up.

So given that I had trouble focussing on this one but still came out of it deeply impressed by it, that makes this a strong recommendation. Read it when you’re not doped up on painkillers, and I can guarantee a good time.

The Death Lesson is out now from Canelo Crime in paperback and ebook. Many thanks for the review copy – sorry the review is a bit late.