Following a number of stunning catastrophes, which have involved him being alternately blown up and insulted in ever stranger regions of the Galaxy, Arthur Dent is surprised to find himself living in a cave on prehistoric Earth. However, just as he thinks that things cannot get possibly worse, they suddenly do. An eddy in the space-time continuum lands him, Ford Prefect, and their flying sofa in the middle of the cricket ground at Lord's, just two days before the world is due to be destroyed by the Vogons.

Escaping the end of the world for a second time, Arthur, Ford, and their old friend Slartibartfast embark (reluctantly) on a mission to save the whole galaxy from fanatical robots. Not bad for a man in his dressing gown...