“And what is it,” said Harrow, in a voice that meant trouble, “that even Palamedes Sextus won’t do?”

“He won’t siphon,” said Dulcinea.

The shutters on Harrow’s face were pulled shut. “And nor will I,” she said.

“I don’t mean soul siphoning … not quite. When Master Octakiseron siphons his cavalier, he sends the soul elsewhere and then exploits the space it leaves behind. The power that rushes in to fill that space will keep refilling, for as long as either of them can survive. You wouldn’t have to send anyone anywhere. But the entropy field will drain your own reserves of thanergy as soon as you cross the line, so you need to draw on a power source on this side of the line, where the field can’t touch it. Do you understand?”

“Don’t patronize me, Lady Septimus. Of course I understand. Understanding a problem is nowhere near the same as implementing a solution. You should have asked Octakiseron and his human vein.”

“I probably would have,” said Dulcinea candidly, “if Pro hadn’t blacked his eye for him.”

“So technically,” said Harrow, acid as a battery, “we’re your third choice.”

“Well, Abigail Pent was a very talented spirit magician,” said Dulcinea, and relented when she saw Harrow’s expression. “I’m sorry! I’m teasing! No, I don’t think I would have asked the Eighth House, Reverend Daughter. There is something cold and white and inflexible about the Eighth. They could have done this with ease … maybe that’s why. And now Abigail Pent is dead. What am I to do? If you were to ask Sextus for me, do you think he’d do it? You seem to know him better than me.”

Harrow pushed herself up from the stairs. She had not seemed to notice that Dulcinea was leaning with her flowerlike face in her hands and drinking in her every movement, nor her expression of carefully studied innocence. Gideon was undergoing complicated feelings about not being the centre of the Seventh’s attention.

With a flourish of inky skirts, Harrowhark turned back to the stairs, staring through Dulcinea rather than at her. “Let’s say I agree with your theory,” she said. “To maintain enough thanergy for my wards inside the field, I’d need to fix a siphon point outside it. The most reasonable source of thanergy would be—you.”

“You can’t move thanergy from place to place like that,” said the Seventh, with very careful gentleness. “It has to be life to death.… or death to a sort of life, like the Second do. You’d have to take my thalergy.” She raised a wasted hand, and then let it flutter back to her face like a drifting paper plane. “Me? I could get you maybe—ten metres.”

“We adjourn,” said Harrowhark.

Harrow grasped Gideon hard around the arm and practically dragged her back up the stairs, out past the foyer and into the hallway. The noise of the door slamming behind them echoed around the corridor. Gideon found herself staring straight down the barrel of a loaded Harrowhark Nonagesimus, hood shaken back to reveal blazing black eyes in a painted white face.

“‘Avulsion’,” she said bitterly. “Of course. Nav, I’m going to bear down hard on your trust again.”

“Why are you so into this?” asked Gideon. “I know you’re not doing it for Dulcinea.”

“Let me make my business plain. I have no interest in Septimus’s woes,” Harrow said. “The Seventh House is not our friend. You’re making yourself an utter fool over Dulcinea. And I dislike her cavalier even more—” (“Massive slam on Protesilaus out of nowhere,” said Gideon.) “—but I would finish the challenge that sickened Sextus. Not for the high ground. But because he must learn to stare these things in the face. Do you know what I’d have to do?”

“Yeah,” said Gideon. “You’re going to suck out my life energy in order to get to the box on the other side.”

“A ham-fisted summary, but yes. How did you come to that conclusion?”

“Because it’s something Palamedes wouldn’t do,” she said, “and he’s a perfect moron over Camilla the Sixth. Okay.”

“What do you mean, ‘okay’—”

“I mean okay, I’ll do it,” said Gideon, although most of her brain was trying to give the part of her brain saying that a nipple-gripple. She chewed at a damp fleck of lip paint and took off her dark glasses, then popped them into her pocket. Now she could look Harrow dead in the eye. “I’d rather be your battery than feel you rummaging around in my head. You want my juice? I’ll give you juice.”

“Under no circumstances will I ever desire your juice,” said her necromancer, mouth getting more desperate. “Nav, you don’t know precisely what this is asking. I will be draining you dry in order to get to the other side. If at any point you throw me off—if you fail to submit—I die. I have never done this before. The process will be imperfect. You will be in … pain.”

“How do you know?”

Harrowhark said, “The Second House is famed for something similar, in reverse. The Second necromancer’s gift is to drain her dying foes to strengthen and augment her cavalier—”

“Rad—”

“It’s said they all die screaming,” said Harrow.

“Nice to know that the other Houses are also creeps,” said Gideon.

“Nav.”

She said, “I’ll still do it.”

Harrowhark chewed on the insides of her cheeks so hard that they looked close to staving in. She steepled her fingers together, squeezed her eyelids shut. When she spoke again, she made her voice quite calm and normal: “Why?”

“Probably because you asked.”

The heavy eyelids shuttered open, revealing baleful black irises. “That’s all it takes, Griddle? That’s all you demand? This is the complex mystery that lies in the pit of your psyche?”

Gideon slid her glasses back onto her face, obscuring feelings with tint. She found herself saying, “That’s all I ever demanded,” and to maintain face suffixed it with, “you asswipe.”

When they returned, Dulcinea was still sitting on the stairs and talking very quietly to her big cavalier, who had dropped to his haunches and was listening to her as silently as a microphone might listen to its speaker. When she saw that the Ninth House pair were back in the room, she staggered to rise—Protesilaus rose with her, silently offering her an arm of support—as Harrowhark said, “We’ll make our attempt.”

“You could practise, if you wanted,” said Dulcinea. “This won’t be easy for you.”

“I wonder why you make that assumption?” said Harrowhark.

Dulcinea dimpled. “I oughtn’t to, ought I?” she said. “Well, I can at least look after Gideon the Ninth while you’re over there.”

Gideon still saw no reason why she would need looking after. She stood in front of the stairs feeling like a useless appendage, hand gripping the hilt of her sword as though through sheer effort she could still use it. It seemed dumb to be a cavalier primary with no more use than a big battery. Her necromancer stood in front of her with much the same nonplussedness, hands working over each other as though wondering what to do with them. Then she swept one gloved hand over the side of Gideon’s neck, fingers resting on her pulse, and breathed an impatient breath.