“Ask me how I am and I’ll scream,” she said.

“How are you,” said Camilla, who was a pill.

“I see you calling my bluff and I resent it,” said Gideon. “So, hey. What do you really use when you’re not pretending the rapier’s your main wield? Two short blades of equal length, or one blade and one baton?”

Her keen eyes narrowed into black-lined slits. “How did I mess up?” she asked, eventually.

“You drew your rapier and your dagger at the same time. And you’re ambidextrous. You keep cutting like both your blades are curved. Also, there’s six swords and a nightstick on your bed.”

“Should’ve tidied my mess,” admitted Camilla. “Two blades. Double-edged.”

“Why? I mean, that’s boss, but why?”

The other cavalier massaged her elbow gingerly, flexing her fingers as though to make sure there was no correlating pain. She seemed to be considering something, and then she came to an abrupt conclusion. “I applied to be the Warden’s cavalier primary when I was twelve,” she said. “Got accepted. We’d looked at the data on weapons, before. Decided that two short blades had—more general applications. I learnt the rapier,”—that was an understatement—“but I’ll be fighting with the blades, when the time comes to really fight.”

Before Gideon could get to grips with the disquieting implication this was not yet the time to really fight, Camilla got in an elbow jab: “Why are you acting like you and he are arguing?”

“Nooooo,” said Gideon brightly, followed up with a: “thaaaaanks.”

“Because you’re not arguing.” Beat. “You’d know if you were arguing.”

“Can you— I don’t know! Can you tell him that if he wants me to introduce him to Dulcinea, I can do it? Can you tell him I’m not trying to cramp his friggin’ style?”

“The last thing the Warden needs,” said Camilla, “is an introduction to Lady Septimus.”

“Then can you tell him to maybe stop acting like he read everyone’s feelings in a book ages ago? Because that would be completely sweet,” said Gideon.

Without another word, Camilla moved to bookend her adept as he paused before a large, gilt-framed picture: the gilt was mostly brown except where it had gone black, and the picture itself was so faded that it looked like a coffee stain. It was a curious image: a dusty expanse of rock, cracked into an enormous canyon running down the centre, a sepia river winding into flaked-off nothingness at the very bottom.

“I documented this one a long time back,” said Harrow.

“Let’s take another look.”

Palamedes and Camilla each shouldered one corner of the portrait, lifting it off some unseen tack. It seemed very light. The great Lyctoral door behind it—with its black pillars and its carved horned skulls, its graven images and grim stone—was not particularly well hidden. In all respects, it was a nearly exact match for the other Lyctoral door Gideon had seen. But Harrow sucked in her breath.

She went to the lock, and then Gideon saw why: it had been filled in with some hard, tarry grey stuff, like putty or cement. Someone had deliberately tampered with the keyhole. Part of the putty had been chipped away at the bottom, with great gouges taken out of it, but otherwise it seemed depressingly solid. There was no getting through that stuff without significant engineering work.

“Sixth,” said her necromancer, “it was not in this condition the first night we were in Canaan House.”

“I still can’t believe you documented every door in this place on the first night,” said Palamedes, with one of his slight dry smiles, “and that I didn’t. I couldn’t tell when the lock was first jammed. I thought I was losing my grip.”

Harrow was already easing her gloves off with her teeth, flexing her long nervous fingers like a surgeon. She drew the pad of her thumb over the stuff, furrowed her brow so deeply that it could have held a pencil, and swore under her breath. She tossed the gloves to Gideon—Gideon caught them neatly—and depressed the matter with her thumb and forefinger. “This,” she said calmly, “is regenerating ash.”

“Perpetual bone, which accounts for it being undateable—”

“Same stuff as the transferral construct.”

“In which case—”

“Whoever put this in place would need to have a comparable level of skill to whoever made the construct,” said Harrow. “Getting it out again would require more power than most bone specialists hold—in aggregate.”

“I didn’t bring you here to remove it,” Sextus said. “I just brought you here to confirm, which you’ve done nicely, thank you.”

“Excuse me. I never said I couldn’t remove it.”

One eyebrow went up above the thick spectacles. “You don’t think…?”

It was the Harrowhark of old who responded, the one who walked down dusty Ninth House halls as though crushing purple silk beneath her feet. “Sextus,” she said blandly, “I am embarrassed for you that you can’t.”

She clapped her hand over the gall of bone matter welted over the lock. Then she drew it back, and—with all the self-affinity of chewing gum or glue—it travelled back with her hand, a gummy web of about a finger’s length, the point of origin vibrating madly as a bead of sweat appeared at her temple. Palamedes Sextus sucked in a breath—and then the stuff snapped back, like flexible plastic, rubbering together sullenly in an immovable lump. Harrow tried again. Her fingers kept flexing in and out impotently, kneading, and she turned her head away and closed her eyes. She stretched the stuff away a whole hand’s length—and then it broke, re-formed, scattered back like a reverse explosion. She tried again. And again; and again after that.

The paint on Harrow’s forehead was shiny with blood sweat now. It bubbled up in greyish-pink rivulets. It shone around each nostril. Before she knew what she was doing, Gideon found that she had moved in to flank her: hiding what she was doing from Sextus’s impassive gaze, rolling up the long black sleeve of her Ninth cloak, mouth moving before her brain did. “Battery up,” she muttered.

It was the first thing Gideon had said to her since Harrow had stalked from the Sixth House quarters, taut with what had seemed to be the world’s most dismissive disappointment, a disdainful black crow of a girl. Her adept opened one baleful black eye.

“Pardon?”

“I said saddle up, sunshine. Come on. You know what to do.”

“I manifestly don’t, and never tell me to saddle up, sunshine ever again.”

“I’m saying to you: siphon me.”

“Nav—”

“Sixth are watching,” said Gideon, brutally.

At the last remark—which was a sledgehammer of a statement, not a stiletto—Harrowhark fell silent. Her expression was resentful in a way that her cavalier could not understand, except to parse it as grim hatefulness that—once again—the only path open to her was that of using her cavalier, a girl who had screwed up so badly as to provide the universe at large with a new understanding of screwup. All she said was, “You don’t have to roll up your sleeve, you nincompoop,” and then the leaching, squirming feeling of siphoning began.