Mostly Harmless

The fifth book in The Hitchhiker's Guide series.

Vogons take over The Hitchhiker's Guide to finish, once and for all, the task of obliterating the Earth. After abruptly losing Fenchurch and travelling around the galaxy despondently, Arthur's spaceship crashes on the planet Lamuella, where he settles in happily as the official sandwich maker for a small village. Meanwhile, Ford breaks into The Guide's offices, gets himself an infinite expense account from the computer system, and then meets The Hitchhiker's Guide, Mark II, an artificially intelligent, multi-dimensional guide with vast power and a hidden purpose. He sends it to Arthur Dent for safety.

Trillian uses DNA that Arthur donated for travelling money to have a daughter, and when Trillian goes to report about a war, she leaves her daughter; Random Frequent Flyer Dent, with Arthur. Random, a troubled teenager, steals The Guide Mark II and uses it to get to Earth. Arthur, Ford, Trillian, and Tricia McMillan (Trillian from an alternate universe) follow her. Random becomes startled by a noise and inadvertently fires her gun at Arthur but misses and kills the ever-unfortunate Agrajag. Immediately afterwards, The Guide Mark II causes the removal of all possible Earths from probability.