In which the tenth planet in the solar system is discovered, an American Trillian has trouble with her handbag, and Ford Prefect discovers something horrible at The Hitchhiker's Guide to the Galaxy offices.

The story begins with the tale of the crew of a Grebulon space ship, who lost all of their memories on the way. They landed on Rupert, the tenth planet in the Earth's solar system. The only bit of their computer memory left tells them to 'monitor', so they do just that.

Arthur has flown around the galaxy for a year and has landed back in ZZ9 Plural Z Alpha in the hope of finding Fenchurch. He is currently on the planet NowWhat (named after the first words spoken on it), and is told a good place to go is the planet Hawalius, a planet of oracles. On arrival, Arthur learns that oracles are going out of business because of future news reports, including those from Trillian.

Zaphod Beeblebrox is back at the offices of The Hitchhiker's Guide to the Galaxy in an attempt to meet Zarniwoop again. Sneaking into the building dressed as a pizza delivery man, he meets with Zarniwoop who promises to explain everything. Ford also sneaks into the building's air vents and finds a robot who he calls Colin. Ford discovers from Zarniwoop that The Guide has been taken over.