'Imagination rules the world': Napoleon's compelling observation underpins Quebecois director Robert Lepage's fourth (but first English language) feature, adapted by John Mighton from his own play. The result of their collaboration is simultaneously an intellectual murder mystery, a philosophical poem about identity and the nature of consciousness, and a luminous romance that embraces different versions of desire as it searches for the unpredictable kernel of affection. Narrative pace derives from an unconventional investigation into the removal - for uneasy scientific ends - of particularly gifted brains from their host skulls. This genre riff threads among encounters between George Barber (McCamus, memorably obsessive in I Love a Man in Uniform) and Joyce (Swinton, with all her familiar and welcome ambiguity) as they meet in different lives, testing intimacy and rejection, marriage and strangerhood. Add mathematical memory games and a community with a three word language ('slab', 'block', 'hilarious') and it's clear the cerebral stakes are high. Tiers of meaning cross-fertilise in an open, associative approach to storytelling, as the sublime cinematography and design tease out a heightened Möbius strip reality that challenges unthinking naturalism. But it's the keen yearning at the film's core (with a marine motif suggesting the oceanic possibilities of the human heart and mind) that anchors the whole conception. Allusive, mysterious and moving, with the ambition of its assembly amplified by the calm beauty of its surface, the film shows Lepage at the peak of his art.