Mnemonic, Riverside Studios, London

Once seen, never forgotten. No show in our time could claim that more fittingly thanMnemonic, Theatre de Complicite's spell-binding meditation on memory and origins now revived some three years after its acclaimed launch. My evening got off to a mildly ignominious start when, on the way to the Riverside Studios, I remarked to a fellow critic, that I couldn't remember where we had first seen the piece. "Here," he drawled, raising a sardonic eyebrow. However, given that I have been haunted by Mnemonic ever since, I am happy to say that it had not been inflated in my memory – if anything, I was shocked by how recollection had slightly dulled my sense of its fierce inventiveness and profound imaginative sympathy.

Complicite chief Simon McBurney once made audiences feel the force of the past's immensity by taking them on a journey – backwards in time, downwards in space – into the dark depths of an underground station in an effort to recreate the experience of the speleologists who uncovered (at Chauvet) the earliest cave paintings known to man. In the bracing blizzard of synchronicities in Mnemonic, it's our moral connectedness to the distant past and to the whole story of the human race that is urgently brought home – "story" being, ultimately, the operative word. When the scientific evidence is too vestigial or ambiguous to admit of proof, there's an honourable need, this show intimates, for sustaining narratives.

With its arresting instantaneous shifts and dreamlike scenic superimpositions, the show pursues two simultaneous detective trails into the past. One is the attempt to reconstruct the history of the ice-preserved corpse of a Neolithic man discovered in the Alps in 1991. The other is a young woman's search across contemporary Eastern Europe for the father she never knew. These quests merge in the harassed mind of her deserted boyfriend (Simon McBurney) and converge thematically when it's suggested that the solution to mystery of the iceman's strange death (alone on a journey, with broken ribs, starving) may be that he, too, was a refugee in flight from a pogrom.

Like flickering connections across the collective synapses, the show's imagery is alive with vivid with echoes and correspondences. There's a beautiful sequence when the boyfriend's wooden chair (a mnemonic of both his father and his girlfriend) collapses to become the spindly puppet of the iceman that the cast carefully guide through a recreation of his lonely death. Throughout, the interweaving of the stories serves to give this Neolithic figure an extraordinarily poignant human immediacy. You genuinely feel that you are related to him. Nowhere does this come over more powerfully than in the final scene. The central image of the show is the naked McBurney in the pose of the iceman's corpse. At the end, though, the whole cast takes it in turns to assume this posture in a ceaseless recurring loop that suggests not just the tumbling cycle of the generations but an acknowledgment that he deserves better than to be treated as a tourist curiosity. They acknowledge their kinship by literally putting themselves in his place. Dwelling on memory and origins, Mnemonic manages to be brilliantly original and unforgettable. Any chance of a West End transfer?

To Saturday (020-8237 1111)