“I hate locked room mysteries”.

The Botanist kills without trace. He sends warnings to people in the public eye who court controversy, toxic people who many would consider deserve to die, and then poisons them, bypassing any security in place to make them die in agony. Washington Poe and his team – analyst Tilly Bradshaw and his boss, DI Stephanie Flynn – are baffled, not just as to how the Botanist is delivering his poison, but what exactly is he up to?

As things escalate, Poe needs all of his concentration to keep up with the killer, but that’s not going to happen. One of Poe’s other closest friends, pathologist Estelle Doyle, is in prison for the murder of her father. Poe knows she’s innocent – he knows her too well – but there is a slight problem of the evidence. She discovered the body, she has gunshot residue on her hands and there was a single trail of footprints in the snow leading to the house – Estelle’s. Poe may hate locked room mysteries, but he’s got two to deal with at the same time…

So, what do we have here? Well, it’s the latest instalment in hands-down my favourite modern thriller series and just for good measure there’s a couple of locked rooms thrown in for good measure. Pretty sure it was my birthday last month, so I’m not entirely sure what I’ve done to deserve this. On paper, it would seem to be a perfect combination – and, of course, being a book it is on paper, so…

… yeah, this is probably my favourite book of the year so far.

It’s hard to say much that’s new about the characters. Over the course of The Puppet Show, Black Summer, The Curator and Dead Ground, a series that hit the ground running and then just accelerated, we’ve seen the lead characters – in particular Poe – grow and develop, to the point where you could just read a book about them having a cup of tea together (probably a herbal infusion for Tilly) and it would be a great way to spend your time. But once again, Mike Craven has introduced an antagonist with a new agenda, new situations for Poe to deal with and new ways for the characters to develop. In fact, at least one of them undergoes a MAJOR change in this one – but sshh, spoilers!

Just in case for those people who got lured in with the phrase “locked room”, I should say that the identity of the killer isn’t really a whodunit. There are plenty of questions as to “howdunit” and while I’ve seen most of the locked room tricks before, I didn’t spot them this time round and they are all fairly clued. Craven gives enough info for the reader to work out how all the shenanigans took place. Carr (who gets a name-check) wrote in The Hollow Man’s locked room lecture that there were only so many ways to kill someone inside a locked room, but it’s the work of the author to hide which method was used, something that is done exceptionally well here.

So fantastic characters, gripping and clever plot – and one more thing I should add, it’s damn funny. I have no idea how some writers balance humour with serial killer stories and often it really doesn’t work. Stuart MacBride does it well, although his humour isn’t to everyone’s taste, but the dialogue here is, on occasion, laugh out loud hilarious. I got some very funny looks from Professor Mrs Puzzle Doctor when I was giggling like an idiot at some of Poe’s dialogue. Don’t get me wrong, this is a serious thriller, but Mike Craven never forgets that this sort of book is entertainment first and foremost. And first-rate entertainment at that.

Basically, this is a near-perfect book. And you don’t have to wait too long for it. The Botanist is out on June 2^nd from Constable in hardback and ebook so if you haven’t met Washington Poe yet, then you’ve got time to read the first four books before then. Many, many thanks to Mike Craven for arranging the review copy.