And Another Thing

The sixth book in The Hitchhiker's Guide series.
Written by Eoin Colfer after Douglas Adams' death.

The story begins as death beams bear down on Earth. Zaphod picks them up, but completely fails to escape the death beams. They are then saved by Bowerick Wowbagger the Infinitely Prolonged, whom they agree to help kill. Zaphod travels to Asgard to get Thor's help. In the meantime, the Vogons are heading to destroy a colony of people who also escaped Earth's destruction, on the planet Nano. Arthur, Wowbagger, Trillian and Random head to Nano to try to stop the Vogons. On the journey, Wowbagger and Trillian fall in love, making Wowbagger question whether he wants to be killed. Zaphod arrives with Thor, who then signs up to be the planet's God. With Random's help, Thor almost kills Wowbagger but instead Wowbagger loses his immortality, then marries Trillian.

Thor then stops the first Vogon attack, and apparently dies. Meanwhile, Constant Mown, son of Prostetnic Jeltz, convinces his father that the people on Nano are not citizens of Earth, but citizens of Nano, so it would be illegal to kill them. Arthur is on his way to check out a possible university for Random, when during a hyperspace jump, he is flung across alternate universes, has a brief encounter with Fenchurch, and ends up exactly where he would want to be. And then the Vogons turn up again to destroy Earth.