The Nether is a play thick with challenging themes; child abuse of course (the plot follows a cyberdetective investigating a man running an online immersive fantasy "realm" where people abuse avatars of children, whose players are nominally adult, consenting and willing) but also the complexities of coercion, the limits of ethical investigation, and the lure of the fluidity of identity available online. The action cuts back and forth between realm and reality, actor and avatar.

Explicit portrayal of abuse and violence is carefully avoided; the play is a series of slippery, disturbing discussions, mostly between Papa (an imperious Rory Grant), the programmer of the darknet child brothel, justifying his business and moral choices and Shannon Hayes, Agent Morris, a fragile foil to his casual dominance and assumptions of immunity from legal and moral judgement. Oxford Student Company Knotworks attack this choppy piece with a chilly and filmic eye; the sound design (by Johnny Danciger) is excellent; the stage is an Escheresque muddle of Edwardian county house and municipal bleakness.

The two avatar characters are perhaps the most interesting. Madeleine Walker's desperately damaged old man playing a little girl to pay off unclearable financial and moral debts is suitably queasy, creepy and freaky, all exaggerated giggles, spaniel devotion and abrupt, horrifying blanknesses; Ieuan Perkins as Woodnut, gaga at the gorgeousness of the polygons in this shiny pixel-polished fantasy world, cuts a fine figure as Papa's next victim.

The play keeps pushing at boundaries, skirting the acceptable, misrepresenting and misleading. The emotional connections are unconvincing, and an awkwardly chummy epilogue seems frankly disgusting; but this is certainly the point. This is no love story, but a demolition of the lie that online imagery can be used to avoid "real real world" abuse, made concrete by the terrible damage done to all concerned.