“But the stone…?” said Lila, still pacing.

“The stone shouldn’t exist,” said Kell. “Once the doors were sealed, every relic from Black London was tracked down and destroyed as a precaution.”

“Obviously not every relic,” observed Lila.

Kell shook his head. “White London supposedly undertook the task with even more fervor than we did. You must understand, they feared the doors would not hold, feared the magic would break through and consume them. In their cleanse, they did not stop at objects and artifacts. They slit the throats of everyone they even suspected of possessing—of having come in contact with—Black London’s corrupted magic.” Kell brought his fingers to his blackened eye. “It is said that some mistook Antari’s marks for such corruption and dragged them from their houses in the night. An entire generation slaughtered before they realized that, without the doors, such magicians would be their only way of reaching out.” Kell’s hand fell away. “But no, obviously not every relic was destroyed.” He wondered if that was how it had been broken, if they’d tried, and failed and buried it, wondered if someone new had dug it up. “The stone shouldn’t exist and it can’t be allowed to exist. It’s—”

Lila stopped pacing. “Evil?”

Kell shook his head. “No,” he said. “It is Vitari. In a way, I suppose it is pure. But it is pure potential, pure power, pure magic.”

“And no humanity,” said Lila. “No harmony.”

Kell nodded. “Purity without balance is its own corruption. The damage this talisman could manage in the wrong hands…” In anyone’s hands, he thought. “The stone’s magic is the magic of a ruined world. It cannot stay here.”

“Well,” said Lila, “what do you intend to do?”

Kell closed his eyes. He didn’t know who had come across the stone, or how, but he understood their fear. The memory of it in Holland’s hands—and the thought of it in Athos’s or Astrid’s—turned his stomach. His own skin sang for the talisman, thirsted for it, and that scared him more than anything. Black London fell because of magic like this. What horror would it bring to the Londons that remained? To the starving White, or the ripened Red, or the defenseless Grey?

No, the stone had to be destroyed.

But how? It wasn’t like other relics. It wasn’t a thing to be tossed in a fire or crushed beneath an ax. It looked as though someone had tried, but the broken edge did not seem to diminish its function, which meant that even if he did succeed in shattering it, it might only make more pieces, rendering every shard its own weapon. It was no mere token; the stone had a life—and a will—of its own, and had shown so more than once. Only strong magic would be able to unmake such a thing, but as the talisman was magic itself, he doubted that magic could ever be made to destroy it.

Kell’s head ached with the realization that it could not be ruined—it had to be disposed of. Sent away, somewhere it could do no damage. And there was only one place it would be safe, and everyone safe from it.

Kell knew what he had to do. Some part of him had known since the moment the stone had passed into his hands.

“It belongs in Black London,” he said. “I have to take it back.”

Lila cocked her head. “But how can you? You don’t know what’s left of it, and even if you did, you said the world was sealed off.”

“I don’t know what’s left of it, no, but Antari magic was originally used to make the doors between the worlds. And Antari magic would have been used to seal them shut. And so it stands to reason that Antari magic could open them again. Or at least create a crack.”

“Then why haven’t you?” challenged Lila, a glint in her eye. “Why hasn’t anyone? I know you’re a rare breed, but you cannot tell me that in the centuries since you locked yourselves out, no Antari has been curious enough to try and get back in.”

Kell considered her defiant smile, and was grateful, for humanity’s sake, that she lacked the magic to try. As for Kell, of course he’d been curious. Growing up, a small part of him never believed Black London was real, or that it had ever been—the doors had been sealed for so long. What child didn’t wish to know if his bedtime stories were the stuff of fiction or of truth? But even if he’d wanted to break the seal—and he didn’t, not enough to risk the darkness on the other side—he’d never had a way.

“Maybe some were curious enough,” said Kell. “But an Antari needs two things to make a door: the first is blood, the second is a token from the place they want to go. And as I told you, the tokens were all destroyed.”

Lila’s eyes widened. “But the stone is a token.”

“The stone is a token,” echoed Kell.

Lila gestured to the wall where Kell had first come in. “So you open a door to Black London, and what? Throw the stone in? What on earth have you been waiting for?”

Kell shook his head. “I can’t make a door from here to there.”

Lila let out an exasperated noise. “But you just said—”

“The other Londons sit between,” he explained. A small book rested on the table by the bed. He brushed his thumb over the pages. “The worlds are like pieces of paper,” he said, “stacked one on top of the other.” That’s how he’d always thought of it. “You have to move in order.” He pinched a few pages between his fingers. “Grey London,” he said, letting one fall back to the stack. “Red London.” He let go of a second. “White London.” The third page fluttered as it fell. “And Black.” He let the rest of the pages fall back to the book.