Theatre-goers are used to solicitous, nannying notices about strobe-lighting, nudity and even cigarette-smoking at the entrance to productions.
So it's refreshing to encounter warnings that drolly up the ante – “Danger of Death”, “Keep Clear – Sheer Drop” et al – as you wander round In The Beginning Was The End, the latest site-responsive promenade piece from Tristan Sharps and dreamthinkspeak.
The company that meditated on Chekhov's Cherry Orchard in a huge, disused Brighton department store and explored the Orpheus myth in a Moscow paper factory now invite you on a journey (lasting about ninety minutes, it's up to you) through the maze of underground passages and rooms that link Somerset House and King's College.
The pre-publicity for the show has boasted about the influence of the Book of Revelations and a drawing by Leonardo da Vinci entitled “A Cloudburst of Material Possessions” which depicts an apocalyptic downpour of man-made objects. So you go in prepared for an equivalently grandiose statement about the ambiguities of “progress”.
What you actually get from this cryptic piece is an experience that is altogether more oddball and puckish, ranging in tones from deadpan comedy to soaring elegiac lyricism. The melancholy joke is that you're plunged into a world that does not realise that it has already been technologically superseded. In the early rooms, you can leaf through sad stacks of defunct computer manuals or watch obsessive white-coated boffins take readings from obsolete equipment, crankily unconscious of their own redundancy.
Then you are swept into a spoof open evening at Fusion International where the bright lights and the bullish corporate branding are undermined by the idiotic pointlessness of the dated gizmos they demonstrate (there's a voice recognition machine, designed to reduce tension, that barks insults back at you with interest but in decidedly wonky English) and where the functionaries who are tasked to write emollient emails to dissatisfied customers grow mutinous. I mustn't give too much away but it is worth sticking with that looped episode because it culminates in an extraordinary vision involving a spiral staircase, naked bodies and a Kafka-meets-Dante foiled dream of escape.
You could argue that the show's idiosyncratic perspective allows it to side-step the hard ethical dilemmas posed by truly state-of-the-art developments such as the growing sophistication of, say, military robots. But its mix of live performance, witty absurdist videos and haunting “happenings” has its own imaginative integrity and is sustained with terrific logistical aplomb.
To 30 March; tickets (via National Theatre) 0207 452 3000