So here’s a witty thing.  A few doors down the road from The Secret Garden, the much-talked-about immersive play I reviewed earlier this week, there’s a rival site-specific performance staged in a rival Regency townhouse.  Above Below has a very different story, and a very different approach to the space it’s in; but in its own way I enjoyed it just as much as its more-vaunted neighbour.

Rather than thrusting us back through time, Above Below grounds us firmly in the present day, with an enthusiastic archivist greeting us in the hallway before launching a tour of the house.  We, unlike our tour guide, can see the ghosts of the people who once lived here – who act out a slow-burning but gently compelling mystery tale, themed around a book of sketches our archivist friend has found.  It’s a clever gambit; there’s no need to hide or explain away the obvious signs of ongoing renovation, and indeed our guide’s infectious enthusiasm for the house itself is a welcome adjunct to the plot.

The opening scenes, below the stairs, were heavy on domestic detail – the minor crisis of an unexpected picnic, the arrangements for the ironing of the ladies’ delicates.  For a while, I worried that I’d signed up to a staged episode of Upstairs Downstairs in which almost nothing would actually occur.  But presently and, in retrospect, predictably, our host turns the page to a sketch which carries a rather more sinister vibe.

Upstairs, it’s a welcome chance to rest our feet in the sitting room, where a casually cruel old lady torments her housekeeper and baits an unwanted French guest (played with élan by Robin Humphrey, a colourful actor who occasionally threatens to steal the show).  Gradually, and with ratcheting menace, the researcher’s questions are answered: who did draw those sketches?  Why are they so dark?  And what happened to the people who lived here?

In the end, the plot didn’t quite live up to its promise: the resolution to the mystery proves somewhat pedestrian, and as we headed back downstairs I was primed for a final twist that never actually came.  But it just sneaks that fourth star thanks to actress Angela Ferns – whose intense portrayal of the deaf-mute Letitia was tender, subtly spooky, and made the play for me.