I bypass Mahogany Row and the sleeping ghosts of management to come, and head for the canteen. Maxine and her friends put some effort into preparing it for the party, and if I’m lucky-

Yup, I’m in luck. Nobody’s taken the decorations down yet. I turn the lights on, hunting around until I see it: a red-and-white stripy stocking stuffed with small cardboard boxes hangs from the corkboard by the dumb waiter. I grab it and dig the boxes out, nearly laddering it in my haste. The canteen’s bare, but the kitchen is next door, and I fumble for the key again, swearing under my breath (why aren’t these things clearly labeled?) until I get the door unlocked. The fridge is still humming. I get it open and find what I was hoping for-a tray of leftovers, still covered in cling-film.

Ten minutes. I run for the staircase, clutching stocking, pin box, and the tray of stale mince pies. In my pockets: conductive marker pen, iPhone loaded with the latest Laundry countermeasures package, and a few basic essentials for the jobbing computational demonologist. I’m still in time as I leg it down two stories. And then I’m at the basement doors. I pause briefly to review my plan.

Item: Get to the incinerator room without being stopped (optionally: eaten) by the night watch.

Item: Get the stocking pinned up above the incinerator, and place the pies nearby.

Item: Draw the best containment grid I can manage around the whole mess, and hope to hell that it holds.

What could possibly go wrong? I plant my tray on the floor, pull out my key ring, and unlock the door to the basement.

It’s funny how many of the pivotal events of my life take place underground. From the cellar of a secret Nazi redoubt to a crypt in the largest necropolis in Europe, via the scuppers of an ocean-going spy ship: seen ’em all, got the tour shirt. I’ve even visited the basement of the New Annexe a time or two. But it’s different at night, with the cold immanence of an approaching dead god clutching at your heart strings.

I walk down a dim, low-ceilinged passage lined with pipes and cable bearers, past doors and utility cupboards and a disturbingly coffinlike ready room where the night staff wait impassively for intruders. No stir of undead limbs rises to stop me-my warrant card sees to that. Forget ghostly illumination and handheld torches-I’m not stupid, I switched on the lights before I came down here. Nevertheless, it’s creepy. I’m not certain where the document incinerator lives, so I’m checking door plaques when I feel a cold draft of air on my hand. Glancing up, I see a frost-rimed duct, so I follow it until it vanishes into the wall beside a door with a wired-glass window which is glowing cheerily with light from within.

Looks like I’ve got company.

I’m about to put my tray down and fumble with the key ring when my unseen companion saves me the effort and opens the door. So I raise the tray before me, take a step forward, and say, “just who the hell are you really?”

“Come in, Mr. Howard. I’ve been expecting you.”

The thing that calls itself Dr. Kringle takes a step backwards into the incinerator room, beckoning. I stifle a snort of irritation. He’s taken the time to change into a cowled robe that hides his face completely-only one skeletal hand projects from a sleeve, and I can tell at a glance that it’s got the wrong number of joints. I lick my lips. “You can cut the Dickensian crap, Kringle-I’m not buying it.”

“But I am the ghost of Christmases probably yet to come!” Ooh, touchy!

“Yeah, and I’m the tooth fairy. Listen, I’ve got a stocking to put up, and not much time. You’re the precognitive, so you tell me: is this where you try to eat my soul or try to recruit me to your cult or something and we have to fight, or are you just going to stay out of my way and let me do my job?”

“Oh, do what you will; it won’t change the eventual outcome.” Kringle crosses his arms affrontedly. At least, I think they’re arms-they’re skinny, and there are too many elbows, and now I notice them I realize he’s got two pairs.

The incinerator is a big electric furnace, with a hopper feeding into it beside a hanging rack of sacks that normally hold the confidential document shreddings. I park the pie tray on top of the furnace (which is already cold enough that I risk frostbite if I touch it with bare skin) and hang the empty stocking from one of the hooks on the rack.

Ghastly hunger beyond human comprehension is the besetting vice of extradimensional horrors-if they prioritized better they might actually be more successful. In my experience you can pretty much bet that if J. Random Horror has just emerged after being imprisoned in an icy void for uncountable millennia, it’ll be feeling snackish. Hence the tempting tray of comestibles.

I glance at my watch: it’s four minutes to midnight. Then I eyeball the furnace control panel. Kringle is standing beside it. “So what’s the story?” I ask him.

“You already know most of it. Otherwise you wouldn’t be here.” He sounds bored, as well he might. “Why don’t you tell me, while we wait?”

“Alright.” I point at him. “You’re here because you’re trapped in a time paradox. Once upon a time the Laundry had a Forecasting Ops department. But when you play chess with the future, you risk checkmate-not to mention being assimilated by that which you study. The first thing Forecasting Ops ever forecast was the probability of its own catastrophic capture by-something. So it was disbanded. But you can’t disband something like that without leaving echoes, can you? So you’re just an echo of a future that never happened.”

The spectral shade in its ragged robe bobs its head-or whatever it has in place of a head.

“The Christmas incursion-” I glance at the cold furnace again, then at my watch “-would have killed you. But without Forecasting Ops to warn us about it, it’d happen anyway, wouldn’t it?” Three minutes. “So you had to maneuver someone into position to deal with it even though you don’t exist.”

I remember sitting through a bizarre and interminable lecture at the Christmas party. But who else remembers sitting through it? Andy doesn’t remember Kringle’s talk. And I bet that aside from my own memories, and a weirdly smudged photocopy-emergent outcome of some distorted electron orbitals on a samarium-coated cylinder-there’s no evidence that the ghost of Christmases rendered-fictional-by-temporal-paradox ever visited the Laundry on a wet and miserable night.

So much for the emergency phone book…

Two minutes. “How far into the future can you see right now?” I ask Kringle. I take a step forward, away from the furnace hopper. “Move aside,” I add.

Kringle doesn’t shift. “The future is here,” he says in a tone of such hollow, despairing dread that it lifts the hair on the back of my neck.

There’s a booming, banging sound inside the furnace. I squint: something writhes inside the tiny, smoke-dimmed inspection window. My watch is slow! There’s no time left. I step close to the control panel and, bending down, hastily scrawl a circle on the floor around my feet.

“Wait, where did the pies come from?” Kringle asks.

I complete the circuit. “The kitchen. Does it matter?”

“But you’re doomed!” He sounds puzzled.

Something is coming down the chimney, but it’s not dressed in fur from its head to its feet, and it doesn’t have twinkling eyes and dimpled cheeks.

“Nope,” I insist. I point at the bait: “And I intend to prove it.”

“But it ate you!” Kringle says indignantly. “Then we all died. I came to warn you, but did you listen? Nooo-”

The trouble with prophecies of your own demise is that, like risk assessments, if you pay too much attention to them they can become self-fulfilling. So I ignore the turbulent time-ghost and stare as the fat, greenish tip of one pseudopod emerges and, twitching, quests blindly towards the frozen pies on top of the furnace.