At the end of a long party, a woman is embarrassed because her husband has not arrived to collect her, as promised. Her hosts have to go, and leave her there. That's when the strange things begin to happen.
Volunteers agree to spend some weeks living exclusively in an underground fall-out shelter, to show what should be done in the event of nuclear war. Near the end of the trial period, they learn that a real emergency is taking place outside.
Mark Carter arranges to visit bank manager Gil Turner. A telephone call tells Turner is wife is being held at gun point. Two of Carter's associates pretend to be police officers expecting a bank raid but events soon spiral out of control.
Miranda Taylor has arranged to meet her husband Frank, for a meal at a local hotel. Frank works for the Drug Squad but held in the cellar by narcotics boss Ehrman. Miranda starts to panic and believes fellow guest Fred Taylor is a killer.
A self-satisfied Londoner heads off for the countryside to spend a dirty weekend with a married woman. On the train, he meets a very odd stranger who is not what he seems to be.