Airline travel is remarkably safe in the twenty-first century: TOM-3748 is the first passenger jet airliner to crash anywhere in the world this month. But it won’t be the last or the largest to do so today.

  The contrails of long-range airline traffic flash silver in the brightening predawn sky above the Yorkshire Dales.

  The Dales lie roughly three hundred kilometers north and a hundred kilometers west of one corner of a sector containing the world’s busiest air traffic. The London/Paris/Amsterdam triangle is occupied by three of the world’s ten busiest airports, along with about a dozen smaller terminals. Transatlantic flights from Europe generally depart along a westerly heading, crossing the Bristol Channel or skirting the southern coast of Ireland. But there are other major international hubs to the south and east, and flights from these airports to destinations on the eastern seaboard of North America tend to fly northwest, directly across the British midlands.

  Flight AZ-602 is an Alitalia Airbus 330 that took off from Rome’s Fiumicino Airport two hours and ten minutes earlier, starting the 7,000-kilometer daily trek to New York. As it cruises over England at 33,000 feet, the cabin crew are serving lunch to the 234 passengers on board. It is half an hour since TOM-3748 sent a smoke-streaked fireball a hundred meters into the sky above Otley, and emergency services from Leeds Bradford Airport in Yeadon are still battling the blaze. A major incident has been declared in the Yorkshire town which lies eighty kilometers to the east of AZ-602’s path, but reports on the ground are confused, with charred bodies and detonated cameras littering the high street. Two police cars are still burning in the center of town. There are no surviving witnesses, and the police superintendent who has been called in is baffled and angry as he tries to establish just what has happened in the early hours of Sunday morning, but the civil authorities do not yet suspect that the explosion of TOM-3748 is not an isolated incident.

  Eighty kilometers away to the northeast, the Marne Barracks at Catterick – the British Army’s largest base – is buzzing like a hornet’s nest that’s been kicked. Soldiers are hastily collecting their kit and prepping light armored vehicles for an unexpected excursion. The approaches to the base are on lockdown and, shockingly, a reconnaissance company with its Scimitar light tanks and a Striker missile carrier has deployed with live ammunition to cover the west of the base. But nobody at Army GHQ has yet realized that the nation’s skies are under attack, much less notified the National Air Traffic Service or alerted the Royal Air Force’s Quick Reaction Force.

  On the heights above Malham, the Host’s theater air defense crew watch the skies. It is a clear, bright day, with a frontal system moving in from the west, threatening rain by afternoon. It is dry, and the feather-edged contrail of AZ-602 is inching its way northwest across the dome of the sky.

  We cannot know what the basilisk crew were thinking. (Subsequent events have rendered that question moot.) Certainly they could not possibly have mistaken the twin-engined Airbus for an enemy firewyrm, or indeed for any other variety of aerial predator from their devastated homeworld. On the other hand, Highest Liege of Airborne Strike had been most specific in her proposal, and with All-Highest’s endorsement the geasa of obedience that bind all the subjects of the Morningstar Empire in thrall lend her operational orders the force of law.

  The air defense crew do not immediately fire on AZ-602. But they painstakingly pull down the saurian necks of their living weapons and double-check the attachment points of their blinkers. They irrigate the monstrous eye clusters cautiously, from well back behind their carefully dulled shields; then the targeting crew installs the newly hatched brain leeches that will direct and aim the basilisks. The watchers use their mage-glass to survey the skies: and presently they identify a second, additional target matching Highest Liege’s specifications.

  American Airlines 759 is another Airbus 330, flying the 8,000-kilometer great circle from Athens to Philadelphia with 195 passengers and nine crew aboard. It has been airborne for nearly three and a quarter hours as it tracks northwest, thirty kilometers south of the Yorkshire Dales, a thousand feet higher than the Alitalia flight.

  AZ-602 is already forty kilometers north of Malham Cove by this point, receding rapidly: it will be out of range of the heavy air defense basilisks within another five minutes. But with AA-759 coming into view from the south, there is plenty of time to line up the basilisks’ heads on both flying machines, and release the blinkers that restrain their lethal gaze.

  Heavy air defense basilisks are not like the close-range, observation-mediated weapons used elsewhere by the Host (and, it must be admitted, by the Laundry’s defensive CCTV network). It is speculated that the large sauropod-like animals evolved their death-stare in an intensely hostile ecosystem, where the airborne apex predators are capable of flocking and stripping a twenty-ton land animal to the bone in minutes. Whatever their origin, their ancestors were acquired by the beastmasters of the Morningstar Empire and developed into a fearsome weapon. Their eye clusters aren’t quite like anything else observed in nature, and the visual cortex that the eight retinas feed into is the size of an elephant’s entire brain. Fortunately they’re herbivorous grazers, and about as clever as a snail – unless something threatens them from above.

  All basilisk processes require a carbon-based target and produce silicon nuclei and hard radiation as their output. (This is one of the reasons why the Host’s soldiers wear silver-plated steel or wrought-iron armor, and part of the reason for the coming catastrophe.) It might be assumed that modern wide-bodied airliners, which for the most part are made of aluminum, would be resistant to a basilisk’s gaze. But such assumptions are misleading.

  Airbus 330s have plenty of non-metallic external surfaces. Like almost all airliners, they are painted in the airline’s livery – using an oil-based paint. Alitalia’s A330s wear the airline livery on their tail fin and fuselage, taking over 200 kilograms of paint. American’s trademark polished silver birds use much less paint, but there is still on the order of 100 kilograms on the tail fin and the fuselage stripe.

  In addition, there are numerous plastic and composite extrusions on the exterior of an airliner. Navigation light housings, antenna shields, and the nose assembly covering the weather radar, are all non-metallic. And the airliner has numerous windows, both portholes for the passengers and windshields for the flight crew.

  To normal eyes, an airliner at cruising altitude is little more than a fly-speck. But the air defense basilisks’ eyes are as sharp as an astronomical camera. They can resolve shapes hidden behind the glass of the cockpit windows, dimly blurred objects behind portholes, heads bent over their lap trays as the passengers eat. And when the basilisks open their eight dinner-plate-sized eyes and stare in terror at the alien sky, the shapes they see flare as bright as the noonday sun.

  A series of explosions ripples through the port side of AZ-602 at seated head-level, spraying red-hot bone fragments through the cockpit and fuselage. There is a ten-meter gap in the line of death where the basilisk’s line of sight is occulted by the wing, then the explosions resume. They are not small, and they are accompanied by the skin of the airliner briefly catching fire from the outside. The surviving passengers – those who do not have window seats – might have time to scream as the hull depressurizes. But the cracks propagate from shattered window to shattered window as the fuselage unzips and the roof opens up like a pod of peas, spilling passengers and banks of seats across the sky as the burning liner abruptly rolls into an inverted dive and falls apart at the seams.

  The American Airlines plane is luckier.

  The cockpit voice recorder tape, when it is replayed, reveals nothing at all out of the ordinary prior to the incident. Then, there is a short few seconds of dialog. Captain Adam Roberts, the pilot, has over 6000 hours logged in airliners of this type, since retiring from the US Air Force. He has his eyes up while First Officer Rachel Moore (700 hours on type) is head down over the instruments, confirming that they have updated their heading towards the next waypoint, just north of Liverpool. Captain Roberts has the aircraft in a turning bank, so that his side of the cockpit is in shadow. On playback we hear Captain Roberts exclaim, “Eyes up, there’s some – someone in trouble, about thirty degrees —”

  Then there is a sound that should never occur on the flight deck of an airliner.

  Two seconds pass as the master caution siren sounds. Captain Roberts is heard to say, “Crap,” then something inarticulate that the cockpit microphones don’t pick up. There are no more words for eight seconds, then he shuts off the master caution alarm, continues the banking turn past the designated waypoint until AA-759 is heading almost due east, and begins to squawk 7700. There is increasing noise in the cabin during this time, and the depressurization warning sounds. Captain Roberts attends to his own oxygen mask, commences a rapid descent, deploys the cabin oxygen masks, and finally calls air traffic control: “American 759 Mayday Mayday Mayday. Request emergency divert to Echo Golf Golf Papa. Hull depressurized and copilot dead. We are under attack…”

  The camera crews are waiting when AA-759 rolls to a stop on the runway at Liverpool’s John Lennon Airport, with scorch marks on the tail fin and filthy black streaks along the fuselage. In the months to follow, AA-759 is going to go down in the books as the airliner that survived despite the odds – except for the unfortunate first officer, whose headless corpse is still strapped into her seat as the blood- and brain-spattered captain shakily pushes back his chair, orders the emergency slides deployed on the taxiway, and collapses. And, of course, the passengers with starboard window seats who receive a crippling dose of radiation from the basilisk stare’s secondary activation isotopes. Forty of them are hospitalized and over the next six months eighteen of them will die. For Captain Roberts, it will be his last flight in the left seat: haunted by awareness that if he hadn’t caused First Officer Moore to look up at exactly the wrong moment she would have lived, he takes early retirement seven months later.

  But at least they survive to tell the tale, unlike the passengers and crew of AZ-602 and TOM-3748 and DL-415, a Boeing 767 with 231 passengers and crew aboard… and many of the residents of Leeds.

  “Nasty little fuckers, likely to stab you in the kidneys as soon as look you in the eye, eh?” Harry says cheerfully as he walks away between two floor-to-ceiling shelving stacks full of ammunition.

  “What would you know about that?” Brains calls after him. Pete trails along in his wake after exchanging a shrug with Pinky. They leave the loaded wooden pallet to fend for itself. It’s not as if anyone is going to steal it while they aren’t watching.

  “Nothing, mate!” Harry calls cheerfully. “Just rumors. But you know there ain’t no smoke without fire. And I’ve got just the thing for you.”

  “Yeah, well, if you put too much faith in rumors in this game you’re going to wake up dead, like all the folks who thought H. P. Lovecraft was a tour guide, not a mad uncle in the attic.”

  “Where are we going, anyway?” Pete asks.

  “Special Countermeasures Collection. I figure you’ve got all the guns you need on that pallet, but if you’re dealing with pointy-eared dogfuckers with ritual magic you’re going to be wanting some better protection, eh?”

  Pinky catches Pete’s eye. “Better protection sounds good,” he says. “Better still, making this someone else’s job…”

  Ahead of them, Harry pulls a bunch of keys that resembles a dead octopus made of tarnished metal and rummages among its tentacles until he finds the right one to open a suspiciously solid-looking door. He swings it open with a grunt of effort. A light flickers on, illuminating the small, windowless room on the other side. It’s lined from floor to ceiling with safe deposit boxes, and Harry moves methodically along the far wall, unlocking one box after another and pulling them out, so that their contents are accessible. “Help yerself, folks, just tell me which box number you’re grabbing so I can keep a record.” Harry steps aside and raises his clipboard expectantly.

  “Unit 904. A dozen horseshoes. Probability weighting 0.14.” Brains, who is reading from a list on his phone screen, shakes his head. “I don’t think so.” He shoves the drawer shut.

  “Probability of what?” Pete is perplexed.

  “Unit 906 —” Brains drawls.

  “There was this analysis project a few years ago,” Pinky explains, sotto voce, “allocating probability of effectiveness to folkloric countermeasures. Very Bayesian, much uncertainty, wow. They fed the results to Forecasting Ops for a second opinion. Upshot: horseshoes and the fair folk don’t match up, although they got our blood-sucking friends bang to rights with short-wavelength ultraviolet.”

  He turns to the next drawer. “This is not a four-leafed clover, but a laser projector that casts a Dho-Nha curve ten meters in diameter across a flat surface a hundred meters away. Close enough to a four-leafed clover to fool someone who doesn’t know what they’re looking at. Probability weighting 0.44, but we’ll take it anyway. Needs a power supply.” This time Brains pulls the drawer fully open and removes something that looks suspiciously like a disco light. “Here, catch.” He passes it carefully to Pinky.

  “Unit 908, grade six heavy-duty reflex wards, collar-mounted, times fifty. I’m taking the lot.” He passes these to Pinky as well; Pinky, hands now full, turns and trots back the way they came in. “Okay, it’s your turn, Vicar…”

  Over the next thirty minutes they loot the Special Countermeasures Collection, transferring half its contents to the pallet of supplies. “There’s no telling which of these items will work,” Brains tells Pete while he checks the second row of drawers, “but if we don’t try them we’ll never find out.”

  “You’re going full Munchkin on our anomaly,” Pete guesses, feeling slightly smug at being able to deploy a term he picked up from his friend Bob Howard: “Is that right?”

  “Insufficient data.” Brains grimaces. “If we knew precisely what’s coming our way we wouldn’t have to guess. But quantity” – he hands Pete a shoebox full of mail gauntlets woven in a non-repeating Penrose tile design – “tends to have a quality all of its own. And this stuff isn’t going to do us any good if we leave it down here.”

  An hour later, the van is parked in the underground car park under Quarry House and most of the contents of the pallet are on the second floor, via a goods elevator. Pete helps Brains move boxes and crates of munitions, esoteric and otherwise, into the empty office suite next to the conference room. The last he sees of Pinky, the tech ops guy is attacking the tow hitch cover on Ilsa the Kettenkrad with a socket set: a fat cylindrical post with a mounting bracket on top waits on the stained concrete beside the half-track.

  It’s four thirty when Pete returns to the conference room at Quarry House, bearing a handful of personal wards. “Brains sent these,” he announces, passing them around the table. Jez Wilson takes one and nods: Lockhart merely twitches his mustache at it. “Class six. He seems to think we may need them. Is there any news?”

  “Vik Choudhury says Ops can’t raise anyone at West Yorkshire Met. They’ve clammed up tighter than an oyster’s arse and there’s word of a whole mess of fatal RTAs – traffic accidents – north and west of here. Police helicopter’s tied up, too. Nobody knows what the hell is going on.” Wilson stares at Pete. Her usual ironic detachment is completely missing, replaced by fear-driven intensity. “OCCULUS haven’t reported back in half an hour. What kept you?”

  “We just shifted nearly a ton and a half of weapons and ammo up from the special countermeasures repository.” Pete pulls out a chair and flops into it. His arms and lower back ache, a reminder that he’s a grown-up with responsibilities and a family rather than an overgrown schoolboy in search of an adventure story to call his own. The sense of responsibility is crushing: so is the nonspecific sense of onrushing doom. “Do we know anything else?”

  “Sit.” Lockhart points at a suspiciously new phone deskset which has materialized on the table in front of Pete’s seat – so new, in fact, that it’s still wearing its protective plastic caul. “If that rings, log it, screen it, and escalate as required.”

  “Is that what I’m here for?” Pete asks. “Because” – he yawns involuntarily – “this isn’t what I’m trained for.”

  “You’re here because you’re a warm body and this is an emergency.” Lockhart’s expression is grim. “Hopefully this is just a full-dress cock-up and you can go home to your bed in a couple of hours. If not, you’ll get a chance to exercise your professional skill set.”

  “What, checking ley lines for signs of drift?”

  “No, Dr. Russell: comforting the bereaved.”

  This puts a damper on the conversation. Meanwhile, other organization staffers drift in and out: lights are coming on throughout this wing of the building as locally assigned employees filter in to their assigned readiness posts. Mrs. Knight from the Arndale office drops by, amiably businesslike. She could be dressed for an afternoon digging over her allotment, aside from the SA80 slung over her shoulder. Nicky Myers from that same office is busying herself along the corridor with a squad of residual human resources, leaning the blue-suited bodies against the wall beside the entrances to stairwells and offices that are in use, mumbling a continuous stream of instructions in Old Enochian (mostly to the effect that the RHRs should refrain from eating anyone wearing a staff ID badge: it needs repeating, for nothing damages one’s attention span like being dead). Pete glimpses other people he half-recognizes through open doorways as the sound of ringing phones and muted conversation rises, along with the electronic whooshing inbox sounds of email applications.

  Pete doesn’t have to wait long before his own phone starts ringing. At first it’s mostly local staff checking in – those who’ve received the alert email or text and who are confirming that they’re expected in the office on a rest day and it’s not just the mail server having a brain fart. (These Pete checks off against the personnel database and reassures that, yes, it is indeed a spot of bother and their assistance would be appreciated.) But the fourth call is different. It’s Emma Gracie, the detective sergeant from the bunker site. “Dr. Russell, have you had any contact from the Territorial Army unit since they cordoned off the site?”