The Hampstead Theatre follows the Royal Court’s example with an offbeat seasonal offering, a Victorian ghost story by Michael Punter that intrigues for a while before collapsing under the weight of its own implausibility.

It starts promisingly, with natural scientist Gabriel Stokes, a Darwinian nay-sayer and staunch Christian, recounting a tale of woe and mystery to a visiting American clairvoyant and trans-medium, Tom Beauregard, and slipping seamlessly on a darkened stage into a spooky re-enactment.

Mark Gatiss was announced as Stokes, but an illness in the family has diverted him, and director Anthony Clark is fortunate indeed in finding Tom Goodman-Hill, outstanding in Enron this year, available. He gives a precise and often funny performance, but this only highlights the play’s schizoid nature. Is it a thriller, or is it a spoof?

Clark’s production tries to have it both ways, as Pamela Miles’ tidily attentive housekeeper Mrs Hinchcliffe refers ominously to the absent master’s nick-nacks in the attic and Stokes reveals his darker purpose in returning to this remote Suffolk fastness on the cliffs: he lost his wife and son at sea, but his short game at golf leaves much to be desired.

There is also an unsatisfactory tangling of stories in the missing Elijah Merchant and the ghostly apparitions of the lost boy. And fifteen years a widower, Stokes is suddenly susceptible to the erotic charms of Vinette Robinson’s mulatto housemaid, Florence Kennedy.

Flo turns out to be gifted medium, but she also has a bastard child who is banished from the premises. So you simply don’t know who’s going to turn up when they start joining hands and asking if anybody’s there. Unforgivably, the Act One “curtain” is too weak and the conclusion tame.

Julian Rhind-Tutt flops effectively around in a fetching red velvet overcoat as the boozed up spiritualist, though his timing is occasionally off. And Paul Farnsworth’s design is a riot of swagging and creaky chandeliers, with lighting and video by Tim Mitchell and Thomas Gray that create phantoms and a storm at sea, though you never quite get what’s going on.

You sit tight, that’s for sure, but it’s a bumpy ride and not always in a good way. Even the pair of sweet tweeting finches in a cage come unstuck, but I do hope they were stiff little doubles, not the real thing... whoops, sorry...