During a demonstration on TV science programme The World Tomorrow, presenter Judith Hann accidentally spills a dangerous liquid and sets off a chain of events that causes the entire population of the world to die. All, that is, except Colin and Brian who meet some time after the devastation has subsided. They don't like each other all that much, but try to make sense and cope with it all by getting on with their old lives - mainly going to the pub and discussing Rugby League. One day they encounter a married couple who have also survived the holocaust, and they set up a mini-community together.