When the usher announces that we are about to led onto the ‘dance floor’, there’s a shiver that runs through the waiting audience in the auditorium of the Festival Theatre – a mix of real trepidation and strange delight. We’ve been divested of shoes, bags and notebooks. We’re excited, but suddenly vulnerable. A hundred or so people seem to turn to each other and murmur anxiously, “…dancefloor? We don’t have to… er… dance, do we?! Isn’t that usually, you know… the dancer’s’ job?” It’s a surprisingly varied crowd awaiting Fleur Darkin’s SisGo, compared to the Festival Theatre’s usual demographic. I can see young teenagers, children even, milling amongst the many pairs of predominantly middle-aged attenders. Yet, in the white socks we’ve been asked to wear, we’re all nearly the same, a little electrified, strangely alert – like the nervy buzz that might take hold of a herd of animals who know something special is about to happen. This isn’t going to be an ordinary show; in fact, it’s already clear it’s not really going to be like a show at all. Certainly not the safe kind of ‘sit back and stare’ kind we might be used to.

We find ourselves on the Festival Theatre’s stage. Suspended above us, a square of neon strip lighting flashes a hallucinogenic blue-red-green-white. It’s a strangely futuristic space, one that feels like it doesn’t exactly exist in this time – the set of an elitist rave nightclub or high-tech research facility from some dystopian sci-fi. The music (from Plastikman, Four Tet, Mortitz von Oswald and others) is like a tangible presence, we all ride it like an irresistible current, an unearthly, nerve-throbbing, muscle-tweaking, beat-heavy dreamscape sort of sound. We soon realise the dance isn’t happening in front of us, but amongst us – seemingly spontaneous eruptions of movement in the form of erotic and quasi-violent struggles or tender duets. It’s impossible to trace the origins or predict the pattern, but it’s thrilling to see the pockets where the dancers perform suddenly magnetise, the crowd drawn almost helplessly to the momentary spectacle. Some audience members hover on the edges, content to watch or simply reluctant to get involved. The dancers throw themselves into and around us with a startling reckless abandon, as if they’re seized by some exuberant force that, only by chance, chooses to leaves the rest of us alone. As the choreography intensifies, separates us out and swallow us up, we eye each other uncertainly. In the half-light, everyone somehow looks like a dancer, and it’s an experience of paranoia and pleasure in equal parts as we try to ascertain who the insiders are. More and more supposed spectators fling themselves into the fray. They know the routine! It’s a joyous conspiracy. The final moments dissolve into a vibrant communal party, and just so you know… we did all dance.

SisGo played at the Festival Theatre as part of the Edinburgh International Festival.