Cornwall, 1910. The country is in something of a panic due to the return of Halley’s Comet and the predictions of some astronomers that the planet Earth’s rotation will send it directly through the tail of the comet, a tail full of deadly cyanogen gases…

Tithe Hall stands on an outcrop, cut off from the mainland at high tide, the ideal place for the Viscount of Tithe Hall to gather people to survive the coming apocalypse. The Hall is sealed from top to bottom, and the houseguests all seal themselves individually in their rooms… And the next morning, the Viscount is found sealed in his study, shot through the eye by an ancestral relic, the crossbow that might have shot Harold Godwinson through the eye at the Battle Of Hastings.

Stephen Pike has just arrived at Tithe Hall as the newest under-butler, fresh out of Borstal for a crime he didn’t commit. Joining forces with Miss Decima, the apparent mad woman in the attic and a maid, Temperance, he sets out to find the murderer – mainly because the local police are convinced that he did it…

Well, this was an unexpected treat. “Downton Abbey meets Knives Out” did worry me a bit, as did comparisons to Wodehouse, but while there is a vein of humour running throughout this one, it’s still a serious mystery novel.

It’s a brilliant reason for a set-up for a locked room mystery – locked room because the victim is found in a room sealed from the inside, not because of the isolated house – and it’s historically accurate, by the way. There are newspaper clippings peppered throughout the book which are, I think, genuine, concerning the comet scare. And it’s got a proper locked room solution too, with hints peppered throughout the narrative as to how it happened – one crucial thing isn’t mentioned until the reveal at the end, but there’s enough stuff to be considered to be playing fair, I think. And there are some very nice tricks along the way…

Oh, and I didn’t spot the murderer, by the way. Just thought I’d mention that.

Most importantly, though, this is damn good fun. Miss Decima is a sweary treat – actually, it’s a bit of a shame how sweary she is, as it might put off some reasons – Temperance makes a great transformation as it becomes clear that she has been underestimated in her job as a maid (she’s an avid fan of Lady Molly of Scotland Yard), and Stephen, the narrator is an absolute gem, with a credible and heartbreaking backstory and the determination to prove himself. The author plays a nice trick with who exactly is the Holmes and who are the Watsons of the group – Miss Decima seems to be all over things at the start, but some of her first ideas are incredibly wrong…

All in all, this is really rather marvellous. A lovely surprise and definitely a book to look out for. And it looks like it’s the start of a series…

The Murder At World’s End is out now from Viking in hardback and ebook. Many thanks for the review e-copy.