Watch: Emilie Hirsch fights invisible aliens in the 'Darkest Hour' trailer

Mean-spirited aliens invade a major city and the military, police and scientists can do nothing to stop them, but a small group of good looking young people can. In "The Darkest Hour," that done-to-death premise undergoes two small spins making it intriguing -- it takes place in modern-day Moscow (the heroes, however, are American tourists) and the aliens are largely invisible.

After jet-setting around the Russian capital, Emile Hirsch, Olivia Thirlby ("Juno"), Rachael Taylor ("Shutter") and Max Minghella ("The Social Network") find the city (and, apparently, the rest of the world) under siege by invisible aliens who feed on electricity. Cars go dead, buildings grow dark (hence the title) and guns seem to have no effect on the beings' force fields. But Hirsch thinks of a way to stop them...hopefully.

Director Chris Gorak, who acted as art director for such iconic auteurs as Terry Gilliam ("Fear and Loathing in Las Vegas"), David Fincher ("Fight Club") and Steven Spielberg ("Minority Report") dealt with a more Earthbound but equally hard-to-see menace in his directorial debut, 2006's "Right at Your Door," in which a terrorist attack results in a deadly chemical gas being unleashed on Los Angeles. "Darkest hour" was produced by Timur Bekmambetov (the director of "Wanted" and "Day Watch").

Not counting the non-stop cartoonish CG extravaganza of the Wachowskis' "Speed Racer," this is Hirsch's first action role and he appears quite confident in the mode of adventure hero. But the real stars here appear to be the low-budget effects, which appear to be an effective answer to the challenge of having a foe that's never actually seen. 
 
"The Darkest Hour" opens nationwide December 23.

What do you think of the trailer?