It ducked into another shadow and waited for her to walk into its claws.

Celaena stopped her retreat as the breathing halted. Silence.

The blue light around her grew brighter.

Celaena put a hand to her chest.

The amulet flared.

It had been stalking the little men who lived above for weeks now, contemplating how they would taste. But there was always that cursed light near them, light that burned its sensitive eyes. There was always something that sent it skittering back here to the comfort of the stone.

Rats and crawling things had been its only food for too long, their blood and bones thin and tasteless. But this female … it had seen her twice before. First with that same faint, blue light at her throat—then a second time, when it hadn’t seen her as much as smelled her from the other side of that iron door.

Upstairs, the blue light had been enough to keep it away—the blue light that had tasted of power. But down here, down in the shadow of the black, breathing stone, that light was diminished. Down here, now that it had put out the torches she’d ignited, there was nothing to stop it, and no one to hear her.

It had not forgotten, even in the twisted pathways of its memory, what had been done to it on that stone table.

With a dripping maw, it smiled.

The Eye of Elena burned bright as a flame, and there was a hiss in her ear.

Celaena whirled, striking before she could get a good look at the cloaked figure behind her. She glimpsed only a flash of withered skin and jagged, stumpy teeth before she sliced Damaris across its chest.

It screamed—screamed like nothing she had ever heard as the ragged cloth ripped, revealing a bony, misshapen chest peppered with scars. It slammed a clawed hand into her face as it fell, its eyes gleaming from the light of the amulet. An animal’s eyes, capable of seeing in the dark.

The person—creature—from the hallway. From the other side of the door. She didn’t even see where she had wounded it as she hit the ground. Blood rushed from her nose and filled her mouth. She staggered into a sprint back toward the library.

She leapt over fallen beams and chunks of stone, letting the Eye light her way, barely keeping her footing as she slipped on bones. The creature barreled after her, tearing through the obstacles as if they were no more than gossamer curtains. It stood like a man, but it wasn’t a man—no, that face was something out of a nightmare. And its strength, to be able to shove aside those fallen beams as though they were stalks of wheat …

The iron doors had been there to keep this thing in.

And she had unlocked all of them.

She dashed up the short stairs and through the first doorway. As she veered left, it caught her by the back of her tunic. The cloth tore. Celaena slammed into the opposite wall, ducking as it lunged for her.

Damaris sang, and the creature roared, falling back. Black blood squirted from the wound across its abdomen. But she hadn’t cut deep enough.

Surging to her feet, blood running down her back from where its claws had punctured, Celaena drew a dagger with her other hand.

The hood had fallen off the creature, revealing what looked like a man’s face—looked like, but no longer was. His hair was sparse, hanging off his gleaming skull in clumpy strings, and his lips … there was such scarring around his mouth, as though someone had ripped it open and sewed it shut, then ripped it open again.

The creature pushed a gnarled hand against its abdomen, panting through those brown, broken teeth as it looked at her—looked at her with such hatred that she couldn’t move. It was such a human expression …

“What are you?” She gasped, swinging Damaris as she took another step back.

But it suddenly began clawing at itself, tearing at the dark robes, pulling out its hair, pushing against its skull, as if it would reach in and rip something out. And the shrieks it made, the rage and despair—

The creature had been in the castle hallway.

Which meant …

This thing, this person—it knew how to use the Wyrdmarks, too. And with its unnatural strength, no mortal barrier would keep it contained.

The creature tipped its head back, and its animal eyes settled on her again. Fixating. A predator anticipating the taste of its prey.

Celaena turned and ran like hell.

Dorian had just passed through the third door when he heard the scream of something not human. A series of crashing noises filled the passage, and the bellowing was cut short with each slam.

“Celaena?” Dorian yelled in the direction of the commotion.

Another slam.

“Celaena!”

Then—“Dorian, run!”

The highpitched shriek that followed Celaena’s command shook the walls. The torches sputtered.

Dorian drew his rapier as Celaena came flying up the stairs, blood leaking from her face, and slammed the iron door shut behind her. She raced toward him, a sword in one hand, a dagger in the other. The amulet on her neck glowed blue, like the hottest fire.

Celaena was upon him in a second. The iron door burst open behind them, and—

The thing that came out was not of this earth—it couldn’t be. It looked like something that used to be a man, but was twisted and dried and broken, with hunger and madness written on every protruding bone in its body. Gods. Oh, gods. What had she awoken?

They sprinted down the hall, and Dorian swore as he beheld the steps up to the next door. The time it would take for them to climb the stairs …

But Celaena was fast. And months of training had made her strong. To his eternal humiliation, as they hit the bottom of the stairs, she grasped him by the collar of his tunic, half-hauling him up the steps. She hurled him into the hallway beyond the threshold.

Behind them, the thing shrieked. Dorian turned in time to see its broken teeth glistening as it leapt up the stairs. Lightning swift, Celaena slammed the iron door shut in the creature’s face.

Only one more door—he could picture the landing that led back to the first hallway, then that spiral staircase, then the second staircase, and—

What then, when they reached the main library? What could they do against this thing?

As Dorian saw the naked terror on Celaena’s face, he knew she wondered the same.

Celaena threw Dorian into the hallway and then hurled herself backward, slamming into the last iron door that separated the thing’s lair from the rest of the library. She put her weight into it and saw stars as the creature barreled into the other side. Gods, it was strong—strong and wild and unyielding …

For a moment, she stumbled away, and it tried to fling open the door. But Celaena lunged, throwing her back against it.

Its hand caught in the door and the creature bellowed, latching its claws into Celaena’s shoulder as she pushed and pushed. Blood ran from her nose, mingling with the blood running down her shoulders. The claws dug in farther.

Dorian rushed to the door, bracing his back against it. He panted, gaping at her.

They had to seal the door. Even if this thing was intelligent enough to know the Wyrdmarks, they had to buy some time for themselves. She had to give Dorian enough time to get away. They would run out of strength soon, and the thing would break through and kill them and whoever else got in its path.

There had to be a lock somewhere, some way to shut it in, to slow it down just for a moment …