Meanwhile, what's up with Zaphod, Ford, and Trillian?
Our intrepid (but not really all that intrepid) explorers are on a solid gold planet, but not really.
Zaphod, Ford, and Trillian, after being knocked out by the gas, wake up to find themselves in a sort of virtual reality catalogue.
These are all the custom planets that Magrathea could build, Ford explains, which really ruins Zaphod's mood, since he likes the idea of a gold planet.
The last planet was full of fish, Ford says, and the next planet has some terribly clashing colors.
So Zaphod, Ford, and Trillian ignore the planet and talk about Zaphod's brain condition. (Condition: Weird.)
Zaphod figures that he sealed off a part of his brain so that no one would know that he knew… something. Unfortunately, he's someone, so he has to hide this info from himself, too.
All of this has to do with a previous president of the galaxy, a guy named Yooden Vranx, whom Zaphod and Ford knew when they were kids.
Right before Vranx died, he visited Zaphod to tell him about the Heart of Gold, saying that Zaphod should steal it but that he would have to hide the reasons why he was stealing it. If not, it would show up on the scans before he was elected president. So that explains why Zaphod caused himself some brain damage. Insert joke here about politicians and brain damage, if you want. It's too easy for us.
At that moment, the catalogue ends and a tall Magrathean tells them that "The mice will see you now" (29.72), which is probably the oddest invitation ever uttered.