Chuck unlocks the first door. “It’s impossible to go from outside to inside in one step. To increase the atmospheric pressure from one atmosphere to two, is equivalent to going underwater about 34 feet. Have you been underwater, and swum down, or jumped off a diving board and went down very far? Going down to ten feet hurts because you haven’t equalized the pressures inside your body and outside.”

He steps inside, invites me through, and closes the door behind us. "Jerry will slowly pressurize this room. You’ll need to breathe a lot and pop your ears a lot. We’re going to six atmospheres, and that’s equivalent to the pressure when 170 feet under water. We do this in seventeen minutes, increasing by about fifteen percent of an atmosphere, or five feet of water depth, every thirty seconds."

“This is like super smart, man,” I say as we wait, popping my ears. I’m pinging with my clicker, and the pressure doesn’t seem to be impacting my ability to echolocate. “You're providing a prison, and you’re increasing thaum generation. Did you figure that out?”

“That wasn't me. Frank was a scuba diver, and had familiarity with explosive decompression. Once Jerry joined us, and had enough air control to pressurize an area, that sealed the deal.”

“Anything else I should know about the associates?”

“There’s nothing interesting in that bunch. I could list their powers, but I don’t think there’s anything worth knowing for you.”

We don’t have much else to say for the next fifteen minutes as the pressure slowly increases. I drum on my legs after a minute of quiet, while Charlie gets a chair, a clipboard, and a pencil from his pocket, then sits down and starts doing calculations or something. Spreadsheets on paper have to suck.

Seventeen minutes and thirty four pressure changes later, my internal timer goes off at the same time Charles gets up. He’s got an internal timer too, or else he’s got communication technique with someone else who does.

He puts his chair, clipboard and pencil away, and opens the second solid metal door. It seems to fit very well into its frame. I guess it has to in order to keep the pressure in.

We walk into a large cavern, basically circular, with the edges all walled off into cells. It has a gothic dungeon kind of vibe. Maybe fifty yards from the center of the cavern to the edges. There are wood, metal, and stone supports holding the seven foot ceiling up. The supports were probably magicked up there, ‘cuz I can’t see that someone would put them up any other way in this world.

There’s fifty cells around the cavern, and people in thirty-four of them. They’re all meditating. I barely notice that it’s thoroughly dark and I’m searing rather than seeing. Then Charlie pulls a couple red thaums out of his pocket, walks over to some pillars, fiddles with them. Apparently, someone bought thaum-fed magic fluorescent lights from their plant-buddy, and installed them here.

“Are you ready to get started?” Charlie is all business.

I figure I ought to be as well. I walk over to the center of the cavern, and start setting up my drum kit. As I do, Charlie announces: “Tax time. You have one minute,” and starts walking around the room. By the time my kit is set up, the minute has passed, and everyone has grabbed thaums from behind their ears, and placed a thaum coin outside their cells, and then retreated back into meditation. Chuck walks around and grabs them all, then looks to me.

“I’m good, Mr. Billingsworth.” I’m trying to let the meditators know that I’m not all the way with the captors. “Maybe check back in a few hours. It’s gonna take me a bit to figure this out.”

“We have someone visit every six subjective hours to collect thaums. One of us will see you then." He steps back into the pressurization room, and closes the door, leaving me alone with 34 prisoners.

First steps first: I have some drumming and experimentation to do. I have to demonstrate that I can do what I say I can do in order to get any leverage at all.

I actually have my whole original drum kit out, with the xylophone, marimba, cowbell, triangle, and tympani. I start warming up again. It takes me twenty minutes, and a run through half a dozen Twenty One Pilots’ songs to be ready to do tests. I can’t do everything the band does, but an awful lot of their work is voice and drums. Tail on the marimba covers most of the rest of it, and when that’s not good enough, I spin around and let my tail handle the drums, while I play with two hands on the marimba. Octuple speed makes all sorts of crazy things possible.

Good drumming is a lot like any other sport. Getting ready to operate at full capacity takes a minute. Warmups, stretches, and those kinds of things are necessary. A lot of the time, you can just play something easy to make sure that all the parts move. Joints in particular should get some slow movement before they move too fast. My elbows and wrists always crack and move slower than they should at the beginning, like there’s sand between my bones.

Now that I’m warmed up, I start testing in earnest. In order to do that, I want a clear picture of the space. I walk around and look. There’s mushrooms in clumps in a bunch of places. I actually have to be careful not to step on them. As I walk around the room, I see that there’s a bunch of holes in the ceiling, and then I notice them in the floors, and in the walls. They're small, quarter-sized holes, and they're everywhere. Using my echolocation, I ping to see what’s in the holes, and I find a bunch of mushrooms in each one I check. They don’t all look to be the same kind, but I’m not a mushroom farmer, so I could easily be wrong. They're at a lot of different depths. And when I look closer, I see that some of the holes actually go to other large caverns.

I walk back over to my kit, and get back to drumming. I play a thaum-attractor rhythm with only one layer. It feels like it’s working. I grab a few ear-thaums, and run it again. A few minutes later, I test my thaum level. Yep. Everything’s working. Wait. I’m in a thaum-enhancing area. My test sucks.

Okay. According to Chuck, I should be able to regenerate two hundred times as many thaums as normal in a given hour. Since it’s normally a sixth of a thaum in an hour, that’s thirty-three thaums if that’s right. I grab the thaums from my ear, and then play for fun, making sure I don’t do any thaum-attractor rhythms.

An hour later, I’ve only regained a few thaums: five or six. Definitely not the thirty-three I was expecting. Why is that? Oh, right. I feel dumb. The extra factor of six is because of time going faster. So I should only get back six every hour. Okay. I'm somewhere near that, but can't tell in detail from that test. My experiments screwed thing up. In order to fix it, I drum a bit with a thaum whorl, and get back my missing thaums quickly. I've at least demonstrated that drumming works some down here.

Across the next few hours, I do the experiments correctly, and determine that I can manage at least the four-layers of thaum-attraction drumming that I need to keep my promises. Well, I’ve got the tests working for me. I don’t know how they will work work for the prisoners on the walls.

Before I know it, I hear the door unlocking, and a moment later it opens, revealing someone new.