Palamedes said: “Princess. You never had any keys. You never saw any of these rooms, except this one.”

“Like I said,” said Ianthe, “I am very, very good, and moreover I’ve got common sense. If you face the challenge rooms, you don’t need the study notes—not if you’re the best necromancer the Third House ever produced. Aren’t I, Corona? Baby, stop crying, you’re going to get such a headache.”

“I came to the same conclusion you did,” said Palamedes, but his voice was cold and inflexible. “I discarded it as ghastly. Ghastly, and obvious.”

“Ghastly and obvious are my middle names,” said the pale twin. “Sextus, you sweet Sixth prude. Use that big, muscular brain of yours. I’m not talking about the deep calculus. Ten thousand years ago there were sixteen acolytes of the King Undying, and then there were eight. Who were the cavaliers to the Lyctor faithful? Where did they go?”

Palamedes opened his mouth as though to answer this question; but he had bumped against something on the back wall, and had gone still. Gideon had never known him to be still. He was a creature of sudden movement and twitchy fingers. Camilla was watching him with obvious suspicion; one of his thumbs was tracing the edge of a black-painted letter, but the rest of his body was rigid. He looked as though someone had turned his power switch off.

But Silas was saying—

“None of this explains why you have killed Naberius Tern.”

Ianthe cocked her head to one side, drunkenly, to take him in. The violet of her eyes was dried-up flowers; her mouth was the colour and softness of rocks.

“Then you weren’t listening. I haven’t killed Naberius Tern. I ate Naberius Tern,” she said, indifferently. “I put a sword through his heart to pin his soul in place. Then I took it into my body. I’ve robbed Death itself … I have drunk up the substance of his immortal soul. And now I will burn him and burn him and burn him, and he will never really die. I have absorbed Naberius Tern … I am more than the sum of his half, and mine.”

Her head hung close to her chest again. She gave a hiccup that sounded a little bit like a sob, and a little bit like a laugh. As she did she appeared blurry and indistinct before them—rocking out of her edges, somehow, unreal. Gideon’s skin had already been crawling, but now it was trying to sprint.

Palamedes said, though he sounded as though he were ten thousand years away, “Princess, whatever you think you’ve done, you haven’t done it.”

“Oh, haven’t I?” said Ianthe.

She rose to stand, but Gideon did not see her move. Ianthe came back to solidity all at once, more real now than anything around her. The room faded into insignificance. She glowed from the inside out, like she had eaten a fistful of lightbulbs. “Do you really deny it, even now?” she said. “God, it makes so much sense. Even the rapiers—light swords, light enough to be held by an amateur … a necromancer. Each challenge—fusing, controlling, binding, utilising—utilising whom? Did you notice that none of those challenges could be completed by yourself? No, you didn’t, and yet that was the biggest red flag. I had to reverse-engineer the whole thing, just from looking at it … all alone.”

Silas sounded quite normal now when he turned and addressed the monotonously crying girl by the slab: “Princess Coronabeth. Is she speaking the truth? And did you, at any point, attempt to stop her, or know as a necromancer what act she was committing?”

“Poor Corona!” said Ianthe. “Don’t get on her case, you little white excuse for a human being. What could she have done? Don’t you know my sister has a bad, sad secret? Everyone looks at her and sees what they want to see … beauty and power. Incredible hair. The perfect child of an indomitable House.”

The Crown Princess of Ida was not acknowledging the fact that anyone was speaking to her. Her sister continued: “Everyone’s blind. Corona? A born necromancer? She was as necromantic as Babs. But Dad wanted a matched set. And we didn’t want anything to separate us—so we started the lie. I’ve had to be two necromancers since I was six. It sharpens your focus, I tell you what. No … Corona couldn’t’ve stopped me becoming a Lyctor.”

Palamedes said, vaguely, “This can’t be right.”

“Of course it’s right, goosey, the Emperor himself helped come up with it.”

“So that is Lyctorhood,” said Silas. He sounded quiet, almost fretful, lost in thought. Gideon thought—just for a moment—that she could see Colum Asht’s throat working, that his pupils had dilated just a very, very little. “To walk with the dead forever … enormous power, recycled within you, from the ultimate sacrifice … to make yourself a tomb.”

“You understand, don’t you?” said Ianthe.

“Yes,” said Silas.

Colum closed his eyes and was still.

“Yes,” repeated Silas. “I understand fallibility … and fallibility is a terrible thing to understand. I understand that if the Emperor and King Undying came to me now and asked me why I was not a Lyctor, I would fall on my knees and beg his forgiveness, that any of us had ever failed this test. May I be burnt one atom at a time in the most silent hole in the most lightless part of space, Lord—Kindly Prince—should I ever contemplate betraying the compact you appointed between him, and you, and me.”

Colum opened his eyes again.

“Silas—” he began.

“I will forgive you eventually, Colum,” said his purse-mouthed uncle, “for assuming I would have been prey to this temptation. Do you believe me?”

“I want to,” said his nephew fervently, with a thousand-yard stare and his missing finger twitching around his shield. “God help me, I want to.”

Ianthe said, contemptuously: “Come off it, you’d drain him dry if you thought it would keep your virtue intact. This is the same thing, just more humane.”

“Do not speak to me anymore,” said Silas. “I brand you heretic, Ianthe Tridentarius. I sentence you to death. As your cavalier is no more, you must stand in for him: make your peace with your House and your Emperor, because I swear to the King Undying you will find no more peace in this life, anywhere, in any world you care to travel to. Brother Asht—”

Harrow said, “Octakiseron, stop it. This is not the time.”

“I will cleanse everything here, Ninth, to stop the Houses from finding out how we have debased ourselves,” said Silas. His cavalier drew his great sword and slipped his calloused, stumped-up fingers into his targe: he had stepped before them all with an expression of something that was too deep into relief for Gideon to really translate it. His adept said: “Colum the Eighth. Show no mercy.”

“Somebody stop him,” said Ianthe. “Sixth. Ninth. I don’t intend for anyone’s blood to be spilled. Well, you know, any more.”

Harrow said, “Octakiseron, you fool, can’t you see—” and Camilla was saying “Everyone back off—”

But Colum Asht did not back off. He came down on Ianthe like a wolf on the fold. He was terrifically fast for such a big, ragged-looking man, and he hit her with such kinetic force that she should have been flung back to splatter on the wall like a discarded sandwich. His arm was true and steady; there was no hesitation in his hand or in his blade.