This topical fable shines a light on the darkest corners of the internet, says Marianka Swain

From Twitter abuse to games and websites indulging our darkest desires, the virtual world is constantly challenging traditional morality and legality. American playwright Jennifer Haley goes a step further in her gripping 2012 dystopian vision of a “real” world overtaken by a sophisticated, immersive internet: The Nether.

This all-consuming realm even has its own law enforcement. Detective Morris (Amanda Hale) is determined to find and destroy the server powering The Hideaway, an eerie evocation of Victoriana where users’ avatars can seduce and murder children. Creator Sims (Stanley Townsend) argues it’s a safe space for “sick” people to live out fantasies without harming others. Morris believes it legitimises and enables violent paedophilia.

To what extent can you police virtual behaviour, or the imagination? This taut 75-minute Royal Court transfer teems with ethical quandaries and startling twists, as Morris’s Orwellian investigation relentlessly unmasks users. Yet it’s difficult to argue for the separation of private role-play and real-life consequence. In this near-future, the physical world is barren, The Nether an increasingly sensuous paradise, leading some users to “cross over” permanently.

Dramatising online activity can be deathly, but Jeremy Herrin’s sure Headlong production boasts a dazzling Es Devlin set, with Luke Halls’ twitching surveillance projections and 3D modelling bleeding into the florid hues of the hyper-real Hideaway. Precocious Iris (Isabella Pappas) offers charming, calculated innocence, enough to make undercover agent Woodnut (Ivanno Jeremiah) forget himself – or, horrifyingly, find himself.

Though Haley gives weight to all viewpoints, with imposing Townsend and David Calder’s addicted punter demonstrating the seductive power of this apparent liberation, she saddles high-strung Morris with daddy issues, making her counterargument unnecessarily schematic. Still, this searingly topical fable plunges you into the depths, from which there is no easy escape.

Until April 25.

Rating: Four stars