Tom and Hester find themselves in a familiar situation: they're in a cage aboard an unfamiliar city.
They watch as Tunbridge Wheels catches up with a smaller city and devours it. Then, they take the strong citizens and put them into cages. The weaker ones they kill.
Tom is appalled, but Hester points out "It's not really so different from what your precious London gets up to" (17.4).
The mayor of Tunbridge Wheels shows up. His name is Chrysler Peavey, and Hester knows him. She convinces him to let them out of the cages. Wow, it's nice to see Chrysler bail someone else out for a change.
What Peavey really wants it to be a man of manners. (Hmm, maybe he should stop shooting people...) He thinks that Tom, as a London gentleman, can teach him a few things.
As Tunbridge Wheels rolls on toward an unknown destination, Tom reluctantly agrees to help.