Leave Harrow to her two broken legs and shattered pelvis. Finding her was an impossibly futile task, in an impossibly large and complex area where you could search all day every day for weeks and not exhaust the floor. It was stupid and it made her feel stupid. And it was Nonagesimus’s own fault for being controlling and secretive about every aspect of her whole ghastly little life. She would not thank Gideon even if she had sat her flat ass in a puddle of molten lava, especially not as Gideon would religiously mark each anniversary of the day Harrow destroyed her butt with magma. She washed her hands of the entire scenario.

After she had choked down food and drunk half a jug of water in quick succession, Gideon gave up and resumed the search. She decided on a whim to go bang on the doors of the lift that didn’t work, and then found that the neighbouring water-swollen door could be opened if you applied force. This revealed a cramped staircase, which she followed down until she burst out into a corridor she’d only once explored. It was a broad, low-ceilinged shaft with *** CAUTION *** tape hollering from every door and surface, but there was one door at the end where people had obviously passed: the tape had snapped and fell in limp ribbons to both sides. The door led to another corridor that was cut off midway by a huge old tarpaulin, which someone had tacked to the rafters to serve as a half-hearted barrier. Gideon ducked under the tarpaulin, turned right, and opened a narrow iron door out to a terrace.

She’d been here once before. Fully half of this terrace had crumbled off into the sea. The first time Gideon had seen it, the whole looked so precarious she had consequently gone down with a fit of acrophobia and beat hasty retreat to somewhere less insane. The sky had seemed too wide; the horizon too open; the terrace too much like a total death trap. The landing dock loomed overhead, and so did the opaque, sweeping windows where the Ninth was housed. Looking up was fine. Looking down, still hundreds and hundreds of metres above the sea, made her want to lose her lunch.

Fuelled by the reminder that the only difference between the drillshaft of Drearburh and the broken terrace was that one was fenced and one wasn’t, she ventured up there again. The wind screamed her into the side of the tower. It was crumbled only at the far end, and the part closest to the trunk of Canaan House seemed intact. Stone windbreakers and dry-soiled, extinct gardens trailed off as far as the eye could see around to the other side, rugged with long stretches of empty planter bed and trellis. Gideon took this path. It was not at all clear—some of the big boxy stone structures had collapsed and the rubble never cleared, and there was really not enough structure still left to distract the eye from the bitten-off terrace that had fallen away to its death—but if you travelled around enough, there was a spiralling staircase of wrought iron and brick clasped to the tower’s bosom.

This was also a bitch to travel up, as the more you climbed, the more of the dead terrace you saw—the sea creaked below, changeful in its colour, a deep grey-blue today and whitecapped with wind—but Gideon readjusted her sunglasses, took a deep breath through her nose, and climbed. The first autodoor she saw, she took, and had to hammer five full times before it silently slid open and gave her entry. Gideon ducked in and pressed against the wall as it slid reproachfully shut, and had to take a minute to collect herself.

It was dark here. She found herself in a long hall that terminated in a left-hand corner. It was very quiet, and very cool. The floor was of pale, cream-and-black tile, set in a starry pattern that repeated itself all the way down the corridor; the paler tiles seemed to float, luminous, as the darker melted into the shadows. Great panes of smoked glass had been set into the walls, lit by dark yellow lamps: sconces held dribbles of mummified candle. It was a wide, shady space, and had something of the inner sanctum of Drearburh about it, just with fewer bones. In fact, there was almost no decoration here. The hall seemed strangely closed in, smaller than the space ought to have been, shrugging inward. The floor was beautiful, and so were the doors—they were wood-inlaid with tiny squares of smoked glass, set smoothly in metal frames. There was a single statue at the end of the corridor where it turned left. It must have once been a person, but the head and arms had been lopped off, leaving only a torso with beseeching stumps. It took her a while to realise that she was in a lobby, and that the doors were elevator lifts: each had a dead screen overhead that must have once shown the floor number.

Gideon folded her sunglasses into a pocket of her robe. Quiet echoes caromed off the walls, up and down, then clarified. Voices floating upward. The stairs at the corner of the hallway led down two short flights, the landing visible below, and Gideon crept down them with careful and noiseless steps.

The indeterminate murmurs thinned into sound—

“—s impossible, Warden.”

“Nonsense.”

“Improbable, Warden.”

“Granted. But still—relative to what, exactly?”

There was some shuffling. Two voices: the first probably female, the second probably male. Gideon risked another step down.

“Six readings,” the second voice continued. “Oldest is nine thou. Youngest is, well, fiftyish. Emphasis ish. But the old stuff here is really very old.”

“The upper bound for scrying is ten thousand, Warden.” Yes, it was a woman’s voice, and not one Gideon had heard: low and calm, stating the obvious.

“The point is here, and you are far over there. Nine thousand. Fiftyish. Building.”

“Ah.”

“Fiat lux! If you want to talk improbable, let’s talk about this”—a scrape of stone on stone—“being three thousand and some years older than this.” A heavy clunk.

“Inexplicable, Warden.”

“Certainly not. Like everything else in this ridiculous conglomeration of cooling gas, it’s perfectly explicable, I just need to explic-it.”

“Indubitable, Warden.”

“Stop that. I need you listening, not racking your brain for rare negatives. Either this entire building was scavenged from a garbage hopper, or I am being systematically lied to on a molecular level.”

“Maybe the building’s shy.”

“That is just tough shit for the building. No; there’s a wrong thing here. There’s a trick. Remember my fourth circle exams?”

“When the Masters shut down the entire core?”

“No, that was third circle. Fourth circle they seeded the core with a couple of thousand fake records. Beautiful stuff, exquisite, even the timestamps, and all of it obviously wrong. Drivel. No one could have believed a word of it. So why bother?”

“I recall you said they were ‘being a pack of assholes.’”

“W—yes. Well, in substance, yes. They were teaching us a particularly annoying lesson, which is that you cannot rely on anything, because anything can lie to you.”

“Swords,” said the woman with a trace of satisfaction, “don’t lie.”

The necromancer—because Gideon had never been so sure in her life that she was listening to a damn necromancer—snorted. “No. But they don’t tell the truth either.”

By now she was almost at the foot of the stairs, and she could see into the room below. The only light came from its centre; the walls were splashed with long shadows, but seemed to be generic concrete, split in places by peeling lines of caution tape. In the centre, lit by a flashlight, was an enormous shut-up metal hatch, the kind Gideon associated with hazard shafts and accident shelters.