The world is tootling along as usual, until the night of the Great Storm. When it's over, billions of people are dead. The only survivors are four people in a car, miraculously shielded. Four people and five billion corpses.
What started out as a light post-war satirical apocolypse became heavy farce part way through. Perhaps this was popular post war, but it didn't quite do it for me. The characters were 2 dimensional and of little interest. The plot could have been good without some of the silliness in the middle. It reminded me of an old book about a couple of guys and a dog boating down the Thames.
If you have nothing to read, give it a shot. If you have an interest in post war literature, try it. Otherwise, find something else.