“Aren’t you coming with us?” she asked.

“I am a demon, Miss Scrivener,” he replied softly.

She looked down at her hands, which had curled into fists. Silas had fought back against Ashcroft as hard as any of them. But if he came with them, the wardens would attempt to kill him on sight. The injustice of it made her sick.

He paused, taking in her expression. “I will accompany you as far as the road. That should be safe enough, as long as I am not seen.”

They recuperated for a few moments longer before Silas vanished into the trees. Elisabeth thought she glimpsed where he had gone: a trembling branch, and a flash of white that might have been a cat’s fur. She helped Nathaniel back to his feet, shooting him a worried glance when he stumbled. Her own dizziness had worn off, but she had only experienced Prendergast’s magic secondhand. Nathaniel shouldn’t even be out of bed in the first place.

A springy mat of needles cushioned their steps as they picked their way down the hill, passing gnarled pines and stones that thrust from the earth like broken bones. Above them, the jagged range of the Elkenspine rose to soaring heights, the summits stark white and imposing against the night sky. Snow streamed from the peaks like pennants, blown loose by the wind. Elisabeth shivered. The wind tearing through the branches seemed to howl forth the landscape’s loneliness and isolation; her ears had already begun to sting from the cold.

Lights glittered ahead, winking between the heaving boughs of fir trees. That was the first glimpse Elisabeth received of the Great Library. When they reached the road and the view opened up, they both trailed to a halt.

They had to tilt their heads back to see the entire structure. It rose skyward like a black citadel, carved straight from the base of the mountain. Lamplight glowered behind its tall, arched stained glass windows, their panes locked away behind iron grilles. Torches guttered along the rampart that circled it in front, so high that Elisabeth couldn’t make out anyone patrolling the top, though she knew the wardens had to be up there, watching.

Warily, they pressed onward. Barricades had been erected on the road, studded with metal spikes facing outward. She and Nathaniel traded a look. The barricades weren’t designed to keep grimoires in—they were made to keep people out. The library was equipped to withstand a siege.

As they finished winding through the barricades, the sound of their footsteps rebounded forbiddingly from the wall. Elisabeth saw no evidence of a gate or doorway in the riveted iron sheets that made up its exterior, towering high above them.

“Hello?” she called up. “Is anyone there?”

Her voice echoed, bouncing back and forth between the high crenellations, a thin and desolate sound. For a moment, all was silent. Then a rumbling, clanging, grinding cacophony answered her—the friction of gears, the awakening of some immense machinery buried within the wall. The ground trembled. A motion at the top of the rampart caught her eye: cannons, swiveling down to aim at them. On second thought, cannons seemed like an inadequate word. The mouth of each gun was wide enough for a person to crawl inside.

She tensed in horror. “They aren’t going to fire on us, are they? Nathaniel?”

His eyes were closed, his face calm, lips moving soundlessly beneath the clamor of the gears. Her ears popped as the air grew heavy with damp. She looked up to see the sky above the Great Library boiling with clouds, their underbellies lit a menacing shade of green.

Figures leaped away from the cannons as a bolt of lightning forked over the rampart, barely missing them. The machinery ground to a halt. A slot slid open above their heads, and a pair of eyes glared down at them. A warden.

“Identify yourself, sorcerer!” he called down.

“Excellent,” Nathaniel said cheerfully. “I’ve gotten your attention. I am Magister Nathaniel Thorn, and this is Miss Elisabeth Scrivener. No doubt our reputations have preceded us. We come with an urgent warning for the Director.”

If their names had any effect on the warden, he showed no sign. In fact, he still looked as though he’d prefer killing them to talking to them. “No one’s allowed in or out of the library. Magisters aren’t an exception. Leave, or we’ll fire.”

“Wait.” Elisabeth tugged on the chain around her neck and pulled out her greatkey, lifting it to the light. She thought back to the conversation she had overheard between Mistress Wick and the Royal Library’s Director. “I promise Director Hyde will want to see us.”

The warden’s eyes widened at the sight of the greatkey, and even further at the mention of the Director’s name. As she had guessed, that name was only known within a select circle. To most people, he was just “the Director.” With luck, the warden would assume she was here on the Collegium’s authority.

Before she could lose her nerve, she continued, “We know the saboteur plans to strike tonight. We’ve come to stop it from happening.” Further inspiration struck. “I carry Demonslayer, the sword of the former Director of Summershall.”

“Show it to me.”

Elisabeth folded her coat aside, allowing the torchlight to glitter on Demonslayer’s garnets. She hoped Irena would understand it being used this way.

The warden’s eyes flicked between her and Nathaniel. Then the slot slammed shut. Gears began rumbling again. But this time, it wasn’t the cannons that moved. A sheet of iron slid aside, revealing a portcullis hidden at the base of the rampart.

“Step inside,” the warden’s voice commanded.

After a hesitation, they obeyed. Colossal wheel-sized cogs churned behind them as the wall rolled back into place. Now they were trapped between the wall and the portcullis, in a sort of outdoor prison cell. The space reeked of machinery grease and was large enough to contain a coach and a full team of horses. Judging by the signs of wear on the flagstones, it often did so. Anyone entering or exiting the Great Library had to stop here first for an inspection.

Past the bars, torchlight lapped across a grim courtyard. The flagstones were crusted with a white rime of what she first mistook for frost, but then realized must be salt.

They waited for several minutes, shifting from foot to foot to stay warm. Finally, the warden appeared on the other side of the portcullis.

“The Director will see you. But there are conditions. No weapons, and you have to wear shackles.” His eyes traveled to Nathaniel. He lifted up a clinking bundle of chains and cuffs. “Iron shackles.”

Nathaniel grimaced. “They’ll keep me from using sorcery,” he explained to Elisabeth under his breath. More loudly he said, “Fine. We accept.”

If Nathaniel was willing to bear having his magic taken away, she wasn’t about to make a fuss about handing over Demonslayer. But she nevertheless experienced a purely physical resistance when she tried. At first her hand wouldn’t release the blade, and the warden had to tug on it, sending a twinge of pain through her injured palm, before her fingers allowed it to slide free. He handed their belongings off to a second warden, who vanished into the shadows. Then Elisabeth and Nathaniel turned around and allowed him to put on the shackles, binding their hands behind their backs.

The portcullis rose with a squeal.

“Follow me,” the warden said.

Their shackles’ chains clinked as they passed between the two grim obsidian angels flanking the door. The wind cut off abruptly when they crossed the threshold, replaced by a dusty silence filled with papery groans and mutterings. A handful of oil lamps did little to dispel the library’s oppressive gloom. Most of the light entered through high stained glass windows, decorated with scenes pieced together in doleful shades of gray and crimson, which cast splintered pools of moonlight on the tall black shelves. A dour-faced librarian glanced their way, then shuffled off into the warren of corridors, his stained robes flapping around his ankles. Elisabeth had heard rumors that librarians considered an assignment to Harrows more of a punishment than a privilege. Now, it wasn’t difficult to see why.