For the third time, Emma and Julian paused in the shadow of a doorway to consult their map. The inside of the tower was nearly featureless—if it weren’t for the map, Emma suspected, they would have been wandering lost for days.

She winced and ached every time she moved. Julian had done his best to patch her up outside the tower, using torn strips from his shirt as bandages. They were so used to functioning with healing runes and the Silent Brothers’ skills, Emma thought, that they never expected to be working hurt, not for more than a brief amount of time. Pushing past the pain where the thorns had driven into her body was exhausting, and she found herself glad for the chance to rest for a moment while Julian stared at the map.

The inside of the tower resembled the inside of a seashell. The corridors twisted around and around in circles, ever narrowing as they ascended, keeping to the shadows. They had discussed whether to use Nene’s potion, but Julian had said they should save it until they absolutely needed it—right now, the corridors were crowded enough with faeries both Seelie and Unseelie that no one was taking too close a look at two hurrying figures in torn cloaks.

“The corridors split here,” Julian said. “One leads down, one up. The throne room isn’t marked on the map—”

“But we know it’s near the top of the tower,” said Emma. “The Queen’s probably already there. We can’t let the King get his hands on the Black Volume.”

“Then I guess we go that way,” Julian said, indicating the ascending corridor. “Keep going up, and hope for some kind of helpful signage on the way.”

“Sure. Because faeries are so big on helpful signage.”

Julian almost smiled. “All right. Keep your hood down.”

They headed up the steeply sloping corridor, their hoods pulled low. As they ascended, the crowds of faeries began to thin out, as if they were reaching rarefied air. The walls became lined with doors, each one more elaborately decorated than the one before, with chips of rare stones and inlaid gold. Emma could hear voices, laughter and chatter, from behind them; she guessed this was the area where the courtiers lived.

One doorway was half-obscured by a tapestry patterned in stars. Standing outside it were two guards dressed in unusual gold-and-black armor, their faces hidden by helmets. Emma felt a shiver of cold as they went by, passing into an area where the corridor narrowed, and narrowed again, as if they were truly winding closer to the heart of a seashell. The torches burned lower in their holders, and Emma squinted ahead, wishing for a Night Vision rune.

Julian clamped his hand down on her arm, drawing her into a shallow alcove. “Redcaps,” he hissed.

Emma peered around the wall. Indeed, two lines of redcaps stood guarding a tall archway. Redcaps were among the most vicious of faerie warriors. They wore scarlet uniforms dyed in the blood of those they had slain. Unusually for faeries, these guards were bearded, with weathered faces. They carried pikestaffs whose metal spearheads were crusted with dried blood.

“This must be it,” Julian whispered. “The throne room.”

He drew the chain with the vial on it over his head, snapped off the top, and swallowed the liquid inside. Emma hurried to do the same, and stifled a gasp. It burned, as if she had swallowed liquid fire. She saw Julian make a pained face before he dropped his empty vial in his pocket.

They stared at each other. Other than the burning in her throat and stomach, Emma felt the same. She could still see her own hands and feet, clear as day, and Julian hadn’t so much as started to get fuzzy around the edges. It wasn’t quite what she’d imagined.

“Nene did say we’d only be invisible to Unseelie faeries,” said Julian quietly after a long moment. His eyes suddenly narrowed. “Emma . . . ?”

“What?” she whispered. “What is it?”

Slowly he raised his hand and tapped his chest, where his parabatai rune was, beneath his clothes. Emma blinked. She could see a dark red glow emanating from the spot, as if his heart itself were glowing. The glow was moving, shifting, like a tiny sandstorm.

“Julian . . .” She glanced down. There was a glow surrounding her own rune too. It was uncanny enough to make her shiver, but she pushed the feeling away and stalked out into the corridor. A moment later Julian was at her side.

The line of redcaps was still there, in front of the dark archway. Emma began to move toward them, conscious of Julian beside her. She could see him clearly, and hear his footsteps, yet as they moved toward the throne room and slipped between the rows of redcaps, no one turned toward them. Not a single redcap appeared to hear or see them.

Emma could see the dark light as if it were strapped across Julian’s chest. But why would an invisibility potion make his parabatai rune glow? It didn’t make sense, but she didn’t have time to wonder about it—they were passing the last pair of redcaps. She felt like a mouse walking blithely in front of an oblivious cat.

A moment later they were over the threshold and inside the throne room of the King.

It was not what Emma had expected. Rather than glimmering gold and rich decor, the room was bare, the floor dark gray stone. The walls were windowless, except for the north wall: A massive glass rectangle looked out onto a blowing nighttime view. The room was scattered with heaps of tumbled boulders, some as big as elephants, many smashed into smaller pieces. It looked like the ruins of a giant’s playground.

There were no seats in the room except for the throne, which was itself a boulder into which a seat had been carved. Stone rose all around its back and sides, as if to shield the King, who sat motionless on the throne’s seat.

In his hands was Julian’s copy of the Black Volume.

As they entered, the King looked up, frowning, and for a moment of panic Emma thought that he could see them. His face was as awful as she remembered it: Divided exactly down the middle as if by a blade, it was half the face of a beautifully striking man, and half stripped skeletal bone. He wore a rich red velvet doublet, a cloak was fastened to his shoulders with rows of golden aiguillettes, and a golden crown bound his brow. A clear vial dangled on a chain around his throat, filled with some scarlet potion.

Reflexively, Emma and Julian ducked behind the nearest heap of broken stone just as four guards strode in, surrounding a woman in white with long dark hair. Behind her marched a young boy with a golden circlet around his head. Two guards accompanied him. They wore the unusual black-and-gold armor Emma had noted before, in the corridor.

She didn’t have much time to think about it, though, because as the woman in white moved into the room, she turned her head, and Emma recognized her.

It was Annabel Blackthorn.

Memory surged in the back of Emma’s throat, a bitter wave. Annabel on the dais in the Council Hall. Annabel, her eyes wild, driving the shards of the Mortal Sword into Livvy’s chest. Annabel covered in blood, the dais swimming with it, Julian holding Livvy in his arms.

Beside Emma, Julian sucked in a harsh, choking breath. He had gone rigid. Emma grabbed his shoulder. It felt like granite: unyielding, inhuman.

His hand was at his belt, on the hilt of a shortsword. His eyes were fixed on Annabel. His whole body was tense with barely leashed energy.

He’s going to kill her. Emma knew it the way she knew each of his next moves in a fight, the rhythm of his breath in battle. She tugged at him, pulling him around to face her, though it was like trying to move a boulder.

“No.” She spoke in a harsh whisper. “You can’t. Not now.”

Julian was breathing hard, as if he’d been running. “Let me go, Emma.”

“She can see us,” Emma hissed. “She’s not a faerie. She will see us coming, Julian.”

He looked at her with wild eyes.

“She’ll raise the alarm, and we’ll be stopped. If you try to kill Annabel now, we’ll both be caught. And we’ll never get the Black Volume back.”

“She needs to die for what she did.” Two harsh red dots burned on his cheekbones. “Let me kill her and the King can keep the goddamn book—”

Emma caught at his cloak. “We’ll both die here if you try!”

Julian was silent, his fingers closing and unclosing at his side. The red glow above his parabatai rune flared like fire, and black lines chased through it, as if it were glass about to shatter.

“Would you really choose revenge over Tavvy and Dru and Ty?” Emma shook him, hard, and let go. “Would you want them to know that you did?”