Invisible alien invaders descend on modern Moscow inside lethal balls of electrical energy in this visually striking but ultimately botched sci-fi thriller. Having survived a massacre of most of the Russian capital\'s population, a group of young tourists led by two cocky American software designers, played by Emile Hirsch and Max Minghella, emerge into the deserted city to search for fellow resistance fighters. At this point they learn the invasion is on an apocalyptic global scale. An international joint venture produced by the globally successful Russian filmmaker Timur Bekmambetov, The Darkest Hour taps into a rich tradition of city-smashing alien-invasion movies that includes The War of the Worlds, Independence Day, Cloverfield and Godzilla. Bekmambetov\'s Day Watch vampire thrillers and flashy Hollywood debut Wanted were hardly subtle, but their appeal lay in their exceptional visual effects, their baroque plot twists and their hyperkinetic energy. The young American director Chris Gorak, meanwhile, earned critical plaudits for his nerve-jangling 2006 debut Right by Your Door. Alas, both the director and producer slip into lowest-common-denominator eurothriller mode here. The 3D special effects are mostly flat and uninspired, though the aliens themselves are admittedly impressive, especially when their electric tentacles zap humans (and dogs) into smouldering pillars of ash. The script is woefully clunky and witless, with no hint of the veiled political or social commentary found in most decent sci-fi thrillers - given Moscow\'s long history of repelling military invasion, any decent screenwriter should have spotted plenty of potential subtext. Worse still, the blandly attractive main characters are so bratty and shallow you may find yourself rooting for the extraterrestrials to microwave them into space dust as soon as possible. In fairness, the handsome Moscow locations make a refreshing change from witnessing US cities blown to rubble in Hollywood disaster movies. It is still an agreeable big-screen novelty to see an eerily empty Red Square, the landmark GUM department store with a crashed airliner poking through its shattered roof, or Stalin\'s monumental art-deco apartment buildings set ablaze by alien death rays. But even here in the fantasy realm of digital effects, Bekmambetov and Gorak seem content with half measures, leaving much of the Russian capital intact despite a full-scale invasion. Either these murderous space monsters are hopeless amateurs, or they are simply not that keen on wiping out mankind. Frustratingly, The Darkest Hour is peppered with promising ideas that are never fully explored. We only ever catch fleeting glimpses of the aliens in their uncloaked state, for example, learning nothing of their cosmic origins nor of the full rationale behind their mineral-hungry strip-mining mission. The second half of the film features post-apocalyptic Cossack horsemen and an eccentric scientist who makes his own Ghostbusters-style blaster weapons, which bodes well for an epic final battle - and yet the big climax turns out to be a low-key gunfight on a runaway electric bus. Another missed opportunity. Aside from its picturesque Moscow setting and its electromagnetic aliens, The Darkest Hour adds little new or exciting to the space-invader genre. Plenty of energy, but not much spark.