THE game's afoot and this particular one is a game of two halves as the Flanagan Collective offers a fresh take on Sir Arthur Conan Doyle's much portrayed character.
Actually that's not entirely true. Writer Alexander Wright sets his story in 1963 so this is a relatively modern Holmes but his familiar traits and idiosyncrasies remain intact, notably his relationship - bromance, even - with sidekick Dr John Watson.
The party games involving the audience in the first half give way to high drama and less frivolity after the interval, during which audience members are set puzzle-solving tasks of their own.
We think we're in the Guildhall council chamber for an illustrated lecture on Holmes and the science of deduction and analysis by York University's professor of criminology Selohm Socklehr. He's not whom he seems. Unscramble the letters and you get ... Well, you don't have to be Sherlock Holmes to work it out.
The lecture is interrupted by the arrival of Dr Watson who's surprised to see his old sleuthing companion as he thought he died three years ago in a fatal encounter with arch-enemy Professor Moriarty at Reichenbach Falls.
Before you can say "elementary dear Watson" we are plunged into a life-or-death race against time as Moriarty is among the audience and keen to gain Holmes's attention. The interactive game-playing gives way to a tense face-off between the two enemies with Watson caught in the middle of a potentially explosive situation. This is when director Tom Bellerby's production is at its best as things get serious and the frivolous, and not always successful, audience participation comes to a halt for swordplay and fisticuffs.
Dominic Allen's Holmes is a bundle of not just energy but ideas that he can't contain in his head and an obsession with ridding the world of Moriarty. It needs a reminder of his friendship with Watson (an Everyman Edward Wren, taking over the role after the original actor had to leave through illness) to make him think straight.
As for Moriarty - that would be telling, wouldn't it?
- Runs until September 21. Box Office: 01904-623568 and yorktheatreroyal.co.uk