When a banking executive tries to outsmart an enormous and seriously pesky rat, it is a case of a battle of wits between two unarmed opponents in this tedious rodent horror treatise on the multiple dangers of rats. Bert Hughes (Peter Weller) is home alone in his Manhattan apartment, trying to work out a major change in his trust company when a noisy rat starts scratching around his periphery, and he becomes obsessed with exterminating it. By the time Hughes is through, his whole apartment is nearly exterminated -- and his friends are keeping their distance due to his rat-mania. (In the middle of a business dinner he brings up the topic of rats served as "stringy chicken" in an Asian country.) Rats may be Of Unknown Origin, but more than their questionable hygiene and genealogy is needed to frighten viewers.