Right now Jonnie's plan is to use the recordings of Terl to build his own control console for the teleporter, which would be easier than trying to steal Terl's console while simultaneously stopping him from detonating his Mystery Fun Box. In the meantime he has to deal with humanity's first defeats in the epic series of skirmishes against the inept and timid alien invaders: an empty ore plane was downed by Hawvins, killing the pilot and copilot, while three Siberians and a Sherpa were slain while hunting near the Russian missile base.
On top of that there's been a setback in defending Edinburgh - the "atmospheric cable" that creates the definitely-not-a-force-field needs a lot of power, but the only power plant nearby is a tidal dam in Bristol, which would leave a long and highly vulnerable target leading up to Scotland's capital. This forces the humans to rely solely on antiaircraft weapons. Meanwhile I'm wondering why the Psychlos kept miles and miles of unused force field components instead of installing them around their bases.
Then there's the chapter's Terl Update. He's churned out "reams of mathematics" which nobody else can make any sense of, and is now working on lots and lots of fuses. Jonnie has a breakthrough when he notices that the materials Terl is working with are identical to the doodads implanted in Psychlo skulls. The aliens have fuses in their brains. I'll let Jonnie explain it.
"All right. Mathematics is logical thought! It is the approximation of being sensible! Now even if a Psychlo has a soul and does his thinking with a soul, or even if he doesn't have, mental action works between those two channels [in the brain].
So long as a Psychlo is thinking logically, there is a constant current between those two nerves. Even asleep there would be a current, a very slight one.
Now up comes an alien. The Psychlo knows his whole race and empire depends upon keeping his mathematics a secret. And the alien wants to know about Psychlo mathematics. The Psychlo instantly shuts off thinking about them. Or a surge occurs and then a shutoff. Pop. Blown fuse!"
...Which occurs when the silver capsule that's regulating logical thought sends the brone thingy that regulates pain and pleasure into a short circuit, driving the Psychlo to violence until he either kills the inquiring alien or himself. Oh, and since Psychlos' moral code restricts them from teaching those "illogical" females any math, when Chirk or some other alien bimbo tries to think about math their silver implant blows, but since they have no bronze implant they just go into a coma instead of a homicidal rage.
But yeah, that's the mechanics of Psychlo mind control. A total load of crap. Logical thought during sleep. Every last Psychlo apparently thinking about math until they see an alien and abruptly stopping, triggering their implants. No Psychlo being willing to sell out their empire and voluntarily discussing math with another species. Kerbango and other intoxicants somehow failing to interrupt this logical thought and thereby triggering the implants. All logical thought passing through a specific nerve bundle in the Psychlo brain. A device that is able to detect when you're thinking about math.
Stupid, but par the course.
And for the moment this revelation is pointless, since the self-proclaimed doctor MacKendrick hasn't perfected the operation to extract the troublesome devices from Psychlo noggins. And so the chapter ends.
Does figuring out Psychlo mind control count as something happening? I mean, Jonnie didn't do anything, but he thought something and then told someone about it. That's kinda like action, right? And there was implied action in the form of aliens shooting up some humans.
Oh hey, looking ahead there's a dogfight in the next chapter. That'll be a refreshing change of pace.
Back to Chapter Five