Will the Ultimate Question to Life, the Universe and Everything (to which the answer is forty-two) be discovered?

Will our heroes be able to control their newly stolen spaceship and the enormous fleet of black battle cruisers that is following them?

Will all end happily or in the certain death that has threatened them so persistently?

Everyone worries about what is going on in the ship. They first discover that the race who the ship belongs to is the Haggunenons, who are able to evolve almost instantly. It turns out that everything in the ship is actually made up of Haggunenons who have evolved into tables, chairs and other things. They then evolve into the Ravenous Bugblatter Beast of Traal. Arthur and Ford escape but Zaphod, Trillian and Marvin are eaten.

Arthur and Ford land on another space ship, belonging to the Golgafrinchams. Meeting the captain in his bath, they claim the ship is one of three 'Arcs' sent to leave their doomed planet. Their arc contains all the 'middle men', whereas the others contain the workers and the rulers. In reality, the Golgafrinchams just wanted to get rid of a useless bunch of middle men. However, the plan backfired when the rest of the Golgafrinchams died of an illness caused by a dirty telephone.

The ship crash lands on their new home planet, which turns out to be Earth, two million years in the past. The Golgafrinchams arrival results in voiding the experiment being carried out by the mice. Arthur and Ford then attempt to find the Ultimate Question by drawing letters from a Scrabble bag. They come up with, What do you get if you multiply six by nine.