Enlightenment, Edward Hall's debut as Artistic Director at Hampstead, is a psychological thriller of the kind that requires an awful lot of disbelief to be suspended.
To give him credit, the production qualities are outstanding and his direction makes the most of the text that Shelagh Stephenson has written.
Designer Frances O'Connor, immensely assisted by artful projections designed by Andrzej Goulding, sets this contemporary drama on a bright, white circular set. This is illuminated by hazy images that occasionally stretch as far as the ceiling. Indeed, so great is the design team's achievement that, had they put in an entry for the Turner Prize, their installation might just have pipped the eventual winner.
For most of the 2¼ hours, this space becomes the living room of the mother and stepfather of Adam, a 20-year-old backpacker who six months earlier, disappeared from the face of the earth.
Thanks to excellent acting from Julie Graham as Lia and Richard Clothier playing Nick, you can almost see the anguish that fills the gap left by the youngster with the whole of life ahead of him.
The couple turn out to be magnets for parasites. In turn, they are visited by Polly Kemp's Joyce, a charlatan medium, Joanna, a TV producer on the make played by Daisy Beaumont, and, in passing, Lia's father Gordon (Paul Freeman). While rather less clichéd than the other pair, he is a former Labour minister who would happily sacrifice his daughter's sanity for a chance to get into Joanna's knickers.
At times during the first half, one can begin to understand the mental pain that parents must suffer due to the uncertainty of whether they will ever again see a much-loved son. The action builds to an interval climax as Adam returns but, in a nice twist, turned out to be an amnesiac impostor.
After the interval, when the visitor turns out to be a psychopath, the big question is why the police did not find out his true identity before introducing him to his so-called parents. As his behaviour becomes more extreme, one also wonders why the very grounded Nick does not call in the authorities.
For those that enjoy psychological thrillers, Enlightenment might be worth a try. Otherwise, Edward Hall is certain to have better things up his sleeve later on in an opening season that also features new plays by Athol Fugard, Mike Leigh and Nina Raine as well as Enda Walsh's Penelope already seen in Edinburgh.
Playing until 30 October
Reviewer: Philip Fisher