Each author kills the thing she loves. But it can work the other way too. In Joanna Murray-Smith’s intriguing drama — a UK premiere — a sensitive publisher’s assistant named Edward Ridgeway (Calum Finlay) visits the ailing crime writer Patricia Highsmith (Phyllis Logan) in her isolated Alpine home. His mission is to get the old battle-axe to write one last novel featuring her greatest creation: the sympathetic sociopath Tom Ripley. As similarities are revealed between Ripley and Ridgeway, the realism of the first half gives way to a lethal authorial anxiety dream. Logan and Finlay make convincing sparring partners, though I would have preferred a nastier, ghastlier Highsmith. Maybe we’ll get one later in the run. For now, this is Murray-Smith’s show. Switzerland is a witty literary game that leaves you debating at least three possible interpretations.