30 Days of Night

This is the story of an isolated Alaskan town that is plunged into darkness for a month each year when the sun sinks below the horizon. As the last rays of light fade, the town is attacked by a bloodthirsty gang of vampires bent on an uninterrupted orgy of destruction. Only the small town's husband-and-wife Sheriff team stand between the survivors and certain destruction.

Plot summary via TMDB