So there are several problems here.

The first one is that his head hurts. Kind of a lot actually.

The second is that he has no idea where he is.

The third is that wherever this is, it looks super ominous.

The fourth is that he doesn't remember how he got here, or, actually, literally anything else before three seconds ago when he opened his eyes and started enumerating problems.

He sits up, rubbing his head, and glares at the guard on general principle.

The guard notices. "Sore head, eh? Can't be worse'n what you did to the other bastard."

"...what did I do to the other bastard?"

"Stabbed him to death, so they say. Then somebody cracked your skull with a barstool. I'd think you'd remember at least one of those things."

"You'd think that! But I don't."

"Huh. You're still going to New Newgate - bloke you murdered is a sergeant's nephew, and he complained to his uncle. And the law doesn't care if you know what you did."

He reflects on this for a moment, then shrugs. The words he's looking for are Sucks to be me, I guess, and it's a pity his dialect doesn't contain them.

The guard shrugs too. "S'a pity, honestly - what are you, sixteen?" 

"Sounds about right!"

"Too old for the orphan-gangs, too young for anything else. Bloody shame."

They come closer to the bars and squint at the prisoner, their keyring dangling from their belt. "It's odd, but I'd swear I knew you from somewhere."

"Yeah? From where?" He steps closer, bringing his face into the light.

The guard squints harder.

Then they shake their head. "No bloody idea. Maybe I saw you running with an orphan-gang ten years ago."

He laughs. "Well, that's still more than I remember about me at this point!"

The guard worries their lip.

Then they seem to make a decision. "Fuck the sergeant's nephew," they decide. "He probably deserved whatever you did to him, and I'm not sending a kid like you to the Spike until you're my age."

They remove a key from their keyring and toss it into the cell. "Anybody asks, you stole that from me. Got it?"

He blinks, surprised, then grins. "Thanks! Yeah, for sure."

"I'm off to get some coffee. Make better decisions about who you stab in the future."

They leave the cell, leaving the prisoner to escape.

He waits until there's no one around, lets himself out, locks it back up behind him because why not, tosses the key back into the cell just to be annoying, and leaves.

No one stops him - a purposeful stride does wonders.

Outside the door of the jail, the city of Fallen London spreads open before him. Watchmaker's Hill, specifically. There's a pub, and an office building with a sign out front reading DEPARTMENT OF MENACE ERADICATION, and at the top of the hill there's an observatory. Around the hill there are marshes, thick with tall treelike mushrooms.

The DEPARTMENT OF MENACE ERADICATION looks interesting! He heads thataway.

Inside, there's a bored-looking man playing solitaire at a wooden desk, along with a few grizzled old men with harpoons chattering with each other. Behind the desk are various posters.

RATS: 11 ROSTYGOLD PER 10. WORRYINGLY LARGE RAT: 200 ROSTYGOLD. SORROW-SPIDER LEGS: 15 ROSTYGOLD APIECE. SPIDER-COUNCIL: 1000 ROSTYGOLD. THE VAKE: 1 MILLION ECHOES.

The Apathetic Secretary looks up from his solitaire. "What you here for, eh?"

"...how big does a rat have to get before it's worryingly large?" he wonders, peering at the assortment of posted rewards.

"That's a bounty on a specific rat," the Apathetic Secretary clarifies. "We call it the Worryingly Large Rat because it's pretty concerning that a rat can get that big. The Department want it dead, but the reward they posted isn't enough for the big-time ratkillers to go for it, so it's sitting there until somebody really needs two echoes' worth of rosty."

"Well, how big is it?"

The Apathetic Secretary gestures. It's about the size of a Doberman.

"Okay, that's pretty big," he acknowledges. "What about the Vake, what the hell's that?"