As we approached the sweating walls and black iron fence of the place, I wondered who would pay even a penny to be buried here. There had once been large trees within the churchyard, but these were only calcified skeletons now, dead for generations, with their amputated arms rising towards the black buildings leaning over the site on every side. The stench from within this walled and fenced space was so terrible that I reached for my handkerchief before remembering that Dickens had taken it earlier in the night to drape across the dead babies. I half expected to see an actual green cloud of miasma hanging over this place and—in truth—there was a sick glow to the mist that had arrived to serve as harbinger for the next warm-blanket of rain.

Dickens reached the high, closed, black iron gate first and tried to open it, but it was locked with a massive padlock.

Thank God, I thought.

But Detective Hatchery reached under his coat and brought a heavy ring of keys from his impossibly burdened belt. He had Dickens hold the bullseye lantern while he fumbled through the clanking keys before finding the one he wanted. It fit in the lock. The huge gate, all black arches and scallops, opened slowly with such a creaking that it seemed as if it had been decades since anyone had paid to open it to rid themselves of a loved one’s corpse.

We walked between the dark headstones and sagging sepulchres, passing under the dead trees and down uneven paving stones on narrow lanes between ancient vaults. I could tell by the spring in his step and the clack of his cane that Dickens was enjoying every second of this. I was concentrating on not retching from the stink and not stepping, in the darkness, on anything soft and yielding.

“I know this place,” Dickens said suddenly. His voice in the darkness was loud enough to make me leap a small distance into the air. “I have seen it in daylight. I have written about it in The Uncommercial Traveller. But I was not within its gates before tonight. I called it the ‘City of the Absent’ and this particular place ‘Saint Ghastly Grim’s.’ ”

“Aye, sir,” said Hatchery. “It once were exactly that.”

“I did not see the skulls and crossbones decorating the iron spikes on the gate,” said Dickens, his voice still far too loud for the circumstances.

“They are still there, Mr Dickens,” attested Hatchery. “I did not feel it politick to shine my light up on ’em. ’Ere we are, sirs. Our entrance to Undertown.”

We had stopped before a narrow, sealed crypt.

“Is this a joke?” I asked. My voice may have sounded a bit brittle to my companions. I was overdue for an application of my medicinal laudanum; the gout was causing many parts of my body to hurt and I could feel a terrible headache tightening like a metal band around my temples.

“No, Mr Collins, no joke, sir,” said Hatchery. He was fumbling at his key ring again and now he set yet another massive key into an ancient lock on the metal door of the crypt. The tall door groaned inward when he leaned his weight against it. The detective shone the light inside and waited for Dickens or me to enter.

“This is absurd,” I said. “There can be no Undertown or underground anything here. Our boots have been squelching in the reeking muck of the Thames for hours. The water table here must be shallower than these graves around us.”

“That does not prove to be the case, sir,” whispered Hatchery.

“This part of the East End lies over rock, my dear Wilkie,” said Dickens. “Ten feet down and it is solid rock. Certainly you know the geology of your city! That is why they chose to build them here.”

“Build what?” I asked, attempting, without total success, to keep the asperity I felt out of my voice.

“The catacombs,” said Dickens. “The ancient underground spaces of a monastery crypt. The Roman loculi before that, even deeper here, almost certainly beneath the Christian catacombs.”

I did not choose to ask what “loculi” meant. I had the sense that I would learn its dark etymology soon enough.

Dickens entered the crypt, then did the detective, then I. The cone of light from the bullseye moved over and around the tiny interior. The pedestal bier in the centre of the small mausoleum, just long enough to hold a coffin or sarcophagus or shrouded body, was empty. There were no obvious niches or other places for bodies.

“It’s empty,” I said. “Someone’s pilfered the corpse.”

Hatchery laughed softly. “Bless me, sir. There was never a corpse ’ere. This partic’lar house o’ the dead is—’as always been—just an entrance to the land o’ the dead. If you’ll move aside, Mr Collins.”

I stepped back against the sweating stone wall at the rear of the crypt as the detective bent low, set his shoulder to the cracked marble bier, and shoved. The sound of stone scraping across solid stone was extremely unpleasant.

“I noticed the arcs gouged into the old pavers as we came in,” Dickens commented to the still-labouring detective. “As clear a clue as the grooves the post of a sagging gate makes in the mud.”

“Aye, sir,” panted Hatchery, still shoving. “But usually leaves and dirt an’ such in ’ere hide that, even in direct lantern light. You’re very observant, Mr Dickens.”

“Yes,” said Dickens.

I was sure that the screech and moans of the slowly shifting bier were loud enough to bring mobs of curious ruffians into the graveyard. Then I remembered that Hatchery had locked the cemetery gate behind us. We were locked in. And since the door of the crypt itself had taken much of Hatchery’s considerable bulk and strength to open—he had shouldered it shut after we entered—we might as well have been locked into this tomb as well. As steep stone stairs became visible in the black wedge beneath the floor now growing wider as the bier was moved, the sense of that weight being set back in place, essentially entombing us below the stone beneath the locked tomb within the locked cemetery, I felt cold shivers running down my back despite the thick heat of the night.

Finally Hatchery stopped pushing and stood upright. The triangular wedge of the dark opening was not large, little more than two feet wide, but when Dickens shone the bullseye down into it, I could see very steep stone steps descending.

Dickens’s face was lighted from below by the lantern as he looked at the detective and said, “You’re sure you will not come down with us, Hatchery?”

“No, sir, thank you, sir,” said the big man. “I have agreed not to.”

“Agreed not to?” Dickens’s tone was one of mild curiosity.

“Aye, sir. An old arrangement that many of us former and current constables and inspectors ’ave with those in Undertown. We don’t go down to complicate their lives, sir; they don’t come up to complicate ours.”

“Rather like the arrangement most of the living attempt to make with the dead,” Dickens said softly, his gaze returning to the dark hole and steep steps.

“Exactly, sir,” said the detective. “I knew you would understand.”

“Well, we should be going down,” said Dickens. “Will you be able to find your way home without a lantern, Detective? We’ll obviously need this one below.”

“Oh, yes, sir,” said Hatchery. “I ’ave another one on my belt should I need it. But I won’t be going ’ome yet. I’ll wait here until dawn. If you’re not back by then, I’ll go straight to Leman Street Station and report two gentlemen missing.”

“That’s very kind of you, Detective Hatchery,” said Dickens. He smiled. “But as you said, the constables and inspectors won’t go below to look for us.”

“Oh, I don’t know, sir,” said the detective, shrugging. “What with you both being famous authors an’ fine gentlemen, perhaps they’d see fit to make an exception in this case. I just ’ope we don’t have to find out, sir.”

Dickens laughed at this. “Come along, Wilkie.”

“Mr Dickens,” said Hatchery, reaching under his coat and coming out with a huge pistol of the revolver variety. “Perhaps you should take this with you, sir. Even if just for the rats.”