Anthony (Ciarán Owens) is a thirtysomething gay man who frequents chemsex parties. He is also our narrator who remembers and reports events as two others on stage (Ian Hallard and Harry Lister Smith) enact these scenes and flashbacks.
He describes how he is being haunted by the ghost of George, a young man he had sex with whose body is found on a mound – a “tumulous” – in a London park. While the police think he died of a GBL overdose, the apparition tells Anthony he was murdered. So begins this “queer noir” as Anthony begins his investigations, sometimes while high.
Hallard and Lister Smith intercept his story to play various characters (police officers, ex-boyfriends, newscasters) with wit and archness. They also orchestrate sound and visual effects, from footsteps on the pavement (a pair of shoes knocked against a cabinet) to spraying the stage with a smoke canister. The lights are dropped at moments of high tension as Owens lights up his face with a torch and strobe lights overhead conjure his cognitive distortions.
Where the result of such meta-theatre that reveals – and revels in – the machinery of its theatre-making might easily have jarred, it works to great, playful effect. It also, ironically, adds to the suspense, even as it removes the fourth wall.
Christopher Adams’s script is taut and propulsive with plenty of social satire that in one excellent scene sends up the north London dinner party set as they serve up balsamic-glazed salads and Peruvian chocolate topped with “a lozenge of champagne jelly.”
Beneath the comedy and mystery are dark themes of family estrangement and homophobic assumptions around the death of young gay men, with references to the Aids epidemic. But these remain under-explored and the motive for murder seems like a too-convenient ending that does not metabolise these bigger themes.
Tumulus’s slick meta-theatre is an original way to deliver a thriller, but in the end, its powerful subject matter feels buried beneath theatrical knowingness and trickery.
• At Soho theatre, London, until 4 May.