Dawn of the Dead (2004)

An unexplained plague has decimated the world's population, and yet the dead aren't dying. They've become zombies, stalking endlessly in a constant quest to feed on the flesh and blood of the few remaining living. A ragtag group of desperate survivors seek refuge in a large indoor mall, where they must learn not only to protect themselves from the ever-increasing zombie horde, but also co-exist with each other as a last bastion of humanity.

Official website: http://www.dawnofthedeadmovie.net