There are many things to love about a Complicite show: the invention, the sense that you are sitting on the leading edge of theatrical evolution, the way connections are made between the epic and the domestic and, perhaps most of all, how the formality of theatre is broken up so completely. Any assumption about what actually constitutes a play or an evening at the theatre is rendered totally redundant.

In this one-man show that sense is fostered right from the start when director/performer Simon McBurney takes to the Barbican's hangar-sized stage looking like a man whose plans have gone awry. They haven't, of course. We are soon being introduced to the cutting-edge sound technology that, in a few moments more, will immerse us in the soundscape of the Amazon. For this, each member of the audience is provided with a set of headphones.

The story is based on Petru Popescu's book Amazon Beaming about the late American explorer Loren McIntyre. This adaptation is part gripping survival story and part anthropological study of the Mayoruna tribe with whom McIntyre made the first significant contact in 1971. Unfortunately, it also indulges the notion that this, and presumably other isolated tribes have the ability to telepathically communicate in a wordless language and also jump to a different, erm, time continuum - or something.

But the thing is McIntyre is not a reliable witness to his own experience. He apparently involuntarily and voluntarily ingested enough hallucinogenic substances to imagine just about anything. And so what's missing here is some healthy scepticism.

Still, the storytelling techniques used by McBurney - who plays both himself and McIntyre - are utterly engrossing. And although it's easy to get lost in some of the more waffly passages about time and language, you could argue that McIntyre did, too, and that therefore, so should we.