When a comet passes close to the earth, machines all over the world come alive and go on homicidal rampages. A group of people at a desolate truck stop are held hostage by a gang of homicidal 18-wheelers. The frightened people set out to defeat the killer machines ... or be killed by them.

Doc McCoy is put in prison because his partners chickened out and flew off without him after exchanging a prisoner with a lot of money. Doc knows Jack Benyon, a rich "business"-man, is up to something big, so he tells his wife (Carol McCoy) to tell him that he's for sale if Benyon can get him out of prison. Benyon pulls some strings and Doc McCoy is released again. Unfortunately he has to cooperate with the same person that got him to prison.