The Far Side of the Moon, Nt Lyttelton, London

The view from planet Lepage

In a laundromat, a man stuffs his clothes through the portholes of one of the washing machines. After a while, he pushes himself in, too, and we see this process, blown up on to a screen and from a reverse angle, so that he seems to be floating like some mad astronaut through the hatch of a spacecraft.

This circular aperture – which can transform itself into everything from a lunar landscape, to the uterine birth canal down which little space-suited human souls are delivered to Earth, trailing their umbilical tethers – is the central metamorphosing image in The Far Side of the Moon, the latest multimedia one-man show by the French-Canadian directorial prodigy, Robert Lepage.

On the 40th anniversary of Yuri Gargarin's first orbit of the Earth, this witty, haunting piece conducts an inner exploration of our need to transcend our terrestrial boundaries. What are we looking for? The Moon, we are told at the start, was once thought to be a huge mirror that reflected the Earth. Do the deepest impulses motivating space travel lie not in scientific curiosity but in narcissism? Astronauts are despatched to send us back aerial snaps of how we look from space. But are we the only creatures who will ever see the Earth from that angle?

The fear of being alone as a species in the universe is paralleled in this piece by the vertigo you suffer as an individual after the death of both parents. Alive, they shielded you from the true view of your own position – homeless on the far side of the Moon, where the comforting Earth cannot be seen. To the accompaniment of Laurie Anderson's varied, otherworldly score, Lepage examines these issues through the story of two brothers (both played by himself) who are trying to come to terms with the demise of their mother. Philippe is a shy, luckless philosopher, struggling to complete his thesis about the effect of space travel on popular culture. Gay André is a successful television weather-man, often to be seen posing in front of a satellite picture of the globe, but as earthbound in his limited materialistic concerns as Philippe is intellectually (and wistfully) questing.

In a show dominated by a revolving overhead mirror, and full of metaphorical reflections, the edgy competitiveness between this pair is designed to echo the US-Soviet space rivalry of the era in which they grew up – the one programme impelled by money and vanity, the other more soulful and genuinely curious about the cosmos.

True, this sibling relationship is a tad schematic, but it is informed throughout by some deliciously droll humour and, as with the symbolic handshake in space during the joint Apollo-Soyuz mission in 1975, it ends in a kind of reconciliation. There has never been any doubt about Lepage's dazzling skill at forging unexpected connections or at conveying these through prodigiously fluent imagery. Here, though, the underlying simplicity and emotional maturity of the way it uses space to looks at human isolation feel like something of a breakthrough in his art.

To the strains of the Moonlight Sonata, the piece ends in an ingenious and uplifting sequence where Lepage simulates the weightless floating of an astronaut, without his body ever leaving the ground. Aptly, in a show much preoccupied by our need, in a Godless universe, to be seen and validated by some other form of intelligence, you wonder how you'd explain the purpose of that bizarre, beautiful, ridiculous stunt to a visiting alien.

To 21 July (020-7452 3000). A version of this review appeared in later editions of yesterday's paper