Where Christoffer Boe's Cannes-wowing 2003 debut Reconstruction told the story of a diffident lover who discovers, after leaving his girlfriend, that the entire world has forgotten who he is, the Danish director's second feature turns this premise on its head.
After being left by his girlfriend Andrea (supermodel Christensen, in her first on-screen role), perfectionist concert pianist Zetterstrøm (Ulrich) has put his past behind him, moving to faraway New York and boxing up memories of what happened to him in Copenhagen, including the one relationship that brought meaning to his life and passion to his music.
Ten years later, Zetterstrøm is persuaded to give a Bach recital back in his native city. There he receives an invitation (with highly unconventional directions) to enter 'the Zone' - an otherworldly, supposedly impenetrable precinct ("where infinity doesn't reach out into the universe, but into the self") that recently sprang up in the heart of Copenhagen.
Once inside its shifting, labyrinthine streets, he pursues fleeting images of a woman whom he can no longer recognise, under the guidance of his mysterious host (and the film's narrator) Tom (Moritzen) - an elderly, wheelchair-bound man who welcomes questions but seldom gives answers.
Like Jean-Luc Godard's Alphaville (from which Boe's production company takes its name), and like Andrei Tarkovsky's Solaris and Stalker (both of which Boe references), Allegro is high-concept, lo-fi science fiction of the mind, where the lack of on-screen pyrotechnics is offset by some very grand ideas about identity, love, memory and art.
It is not that Allegro looks in any way bland - on the contrary, Boe has combined a number of different film stocks, and some charmingly childlike hand-drawn animation to evoke Denmark's fairytale capital as a city of dreams, delusions and delirium. But anyone seeking laser guns, robots, aliens, explosions, or any of the other furnishings typical of blockbuster SF had best look elsewhere; for Boe's speculative fiction is more like a Kafkaesque kitchen-sink drama, close to the spirit (if not quite the letter) of Dogme 95, and less concerned with extraterrestrial beings than with their all too human counterparts. The only android here is Zetterstrøm himself, willfully detached from his own finer feelings, and (apparently) incapable of love or trust.
It does not, in the end, seem to matter whether the film's events unfold in a real (outer) space or entirely within the confines of Zetterstrøm's head, whether Tom is his benefactor or tormentor, or indeed whether Andrea ever existed at all or is just a hidden spark of desire that Zetterstrøm has skillfully repressed since his first childhood kiss - for as the punning musical title Allegro suggests, Zetterstrøm's amnesiac odyssey is as much allegory as straight story, mapping out a lost soul's painful journey to self-knowledge.
Zetterstrøm's dispassionate aloofness tends to infect the whole of Allegro with a chilly quality that extends even to the romantic scenes that he shares with Andrea. But this is all essential to the film's portrait of an artist as an incomplete man, and serves to keep the pianist's underdeveloped emotions, not to mention Christensen's relative inexperience as an actor, well below the icy surface (in cold, cold Copenhagen).
Still, even if it is ultimately left to viewers to invest the film's blank dreamscapes with the warmth of their own experience and memories, what remains is a precisely modulated work that, like Zetterstrøm, only occasionally strikes a false note. It is, however, a pity that it uses up all its best themes in its first half, and ends with one of the most anticlimactic final lines in living memory.