In consequence of a number of stunning catastrophes, Arther Dent is surprised to find himself living in a hideously miserable cave on prehistoric Earth. However, just as he thinks that things cannot possibly get any worse, they suddenly do. He discovers that the galaxy is not only mind-bogglingly big and bewildering, but also that most of the things that happen in it are straggeringly unfair. This is volum three in the trilogy of five.