"But why do you live underground?" Willbury asked in a puzzled voice. Arthur paused for a few moments.
"I'm… I'm not really sure. Grandfather always tells me he'll explain when I'm older." (5.51-52)
Grandfather's past is so mysterious that he doesn't even know why he lives where he does. Of course, this may have to do with how Grandfather has been accused of a crime he didn't commit, as we find out later in the story.
"This business with the cheese hunting? It's been illegal for years now. In the old days it was the Cheese Guild that did the hunting, but the Guild was said to have died out when the trade was banned." (10.22)
Here we get a glimpse into Ratbridge's past. The Cheese Guild used to be super-powerful, apparently, but that all went down the drain when the pollution ruined the industry. In theory the Guild petered out and no longer exists… but now Arthur and his friends have found evidence to the contrary. What's that saying about history repeating itself?
"Marjorie was my clerk. Very bright woman." (14.10)
Willbury has a past connection with Marjorie, and this is going to help him help Arthur. Willbury's career as a lawyer was apparently very full of these kinds of connections, as he seems to know a lot of people around town.
Rumor had it they had a long and interesting history, and that before they turned their hands to laundry, they had been an altogether less respectable crew, but nobody in Ratbridge knew that much about them yet. (16.1)
Got to love the rumor mill. The crew of the Ratbridge Nautical Laundry was, in all likelihood, a band of pirates before they showed up in this sleepy little town… but who can prove it? It seems like they've been smart enough to not announce to everyone that they've had a shady past, which helps, of course.
"Herbert, we grew up on the same street! We played together, got measles together… and got our ears clipped together. Don't you remember burning a hole in my mum's carpet with the toy steam engine we tried to build?" (39.5)
Here, Grandfather reminisces with Herbert about their past in order to try to jog his memory. Apparently their past includes a lot of time spent together, doing the kinds of things boys would do in Ratbridge (which we guess includes setting carpets on fire). Luckily the tales of their past adventures start to get Herbert remembering things again.
"Ratbridge was founded on the cheese, but when new industries came to town, the smoke and waste they produced poisoned the water supply and a lot of countryside around it. It got so bad that the local cheeses were decreed unfit to eat, and the cheese industry collapsed. The cheese barons went bankrupt overnight." (39.20)
Thanks, Grandfather, for this brief history lesson about Ratbridge. It seems like the history of industrialization played out there like it did in a lot of other places, bringing pollution and disruption into the town. This affected the cheese barons, which set Snatcher up to run his evil plot to try to restore the Cheese Guild to its former glory.
Without this background, we wouldn't have a sense of why Snatcher—who comes from a cheese baron family—is so desperate for revenge on the town.
"That's why everything went green. They must have had some more Oil of Brussels and smothered me with it. That's why me memory is so bad!" Herbert fumed. (39.58)
This is where Herbert makes the connection with past events and his memory loss: It's not just that he's always had a bad memory, it's that Snatcher poisoned him with a potent plant-derived oil that can cause permanent memory loss and other trauma. Poor Herbert. At least his memory seems to be slowly coming back.
"Yes, my brothers! We shall use our leviathan to overthrow those that have held us down for so long! First we shall remove their government, then destroy their banks, smash their factories, and return Ratbridge to follow an open free trade in cheesy products!" (48.22)
Here Snatcher elaborates on his evil plan to right the wrongs of the past. It's interesting to notice where he places the blame for things having gone south for Ratbridge's cheese industry. Apparently it was everyone else's fault (the government, the banks, and so on) that the cheese industry had to be shut down, and it didn't have anything to do with the cheese industry selling poisoned cheese. Convenient.
"Do you remember a case many years ago where a man was poisoned with Oil of Brussels in a local hostelry?" Willbury questioned the Chief Squeaker. (53.33)
Willbury is all about righting past wrongs, and this is exactly what he sets out to do by asking the local police chief if he remembers that poisoning case from oh so long ago. Now that Herbert has been found and freed, they have another witness in the case, which should help clear Grandfather's name and instead pin the blame where it truly belongs: on Snatcher.
For the rest of the day Arthur sat by Grandfather, who insisted on telling him stories of Herbert's and Grandfather's youth. Herbert's memory continued to improve as story after story unfolded, and Arthur could hardly bear to tear himself away from them, but they kept needing fresh top ups of cocoa and biscuits from the galley. (54.9)
Happily, Herbert continues to get his memory back. It probably helps that Grandfather was there for a lot of Herbert's formative years since they were childhood buddies. At the same time, Arthur gets to learn about his closest and only family member's past, which is a plus. All's well that ends well, right?