Mostly Harmless

Finally, in Mostly Harmless (published in 1992), Vogons take over The Hitchhiker's Guide (under the name of InfiniDim Enterprises), 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 of simple, peaceful people. Meanwhile, Ford Prefect breaks into The Guide's offices, gets himself an infinite expense account from the computer system, and then meets The Hitchhiker's Guide to the Galaxy, Mark II, an artificially intelligent, multi-dimensional guide with vast power and a hidden purpose. After he declines this dangerously powerful machine's aid (which he receives anyway), he sends it to Arthur Dent for safety ("Oh yes, whose?"—Arthur).

Trillian uses DNA that Arthur donated for travelling money to have a daughter, and when she goes to cover a war, she leaves her daughter Random Frequent Flyer Dent with Arthur. Random, a more-than-typically troubled teenager, steals The Guide Mark II and uses it to get to Earth. Arthur, Ford, Trillian, and Tricia McMillan (Trillian in this alternate universe) follow her to a crowded club, where an anguished Random becomes startled by a noise and inadvertently fires her gun at Arthur. The shot misses Arthur and kills a man (the ever-unfortunate Agrajag). Immediately afterwards, The Guide Mark II causes the removal of all possible Earths from probability. All of the main characters, save Zaphod, were on Earth at the time and are apparently killed, bringing a good deal of satisfaction to the Vogons.