Later, Rose would try to remember the exact moment she stopped believing Mara would stand beside her no matter what, and she would fail every time, because there was no single moment. There was only a door that locked from the wrong side, and a face she had trusted since she was seventeen years old, gone gray and desperate in a torchlit hallway underground.
But that came after. First there was the descent.
⁂
"You can't even stand without the wall," Rose said, watching Lucien brace himself against the doorframe of his own study, his shoulder rebandaged so tightly it had to be cutting off feeling to half his arm. "You are not coming down there."
"I am the only person in this house who knows the layout of the ritual hall beneath it, and the only one Isolde will hesitate to kill outright, because she still needs the bond intact more than she needs me dead this particular hour." He straightened, and the effort it cost him showed plainly enough that Rose did not bother arguing the point further, only filed it away as one more thing to watch for once they were moving. "I'll slow you down less alive and useful than I will lying here imagining what's happening to your brother."
Mara arrived within the hour, called back the moment Rose's message reached her, and the sight of her friend crossing the threshold of Blackthorn a second time, this time with a crowbar in one hand and no pretense of caution in her face at all, was the first thing all day that made Rose's chest loosen even slightly.
"Tell me the plan," Mara said.
"We don't have one beyond get there before she finishes whatever she's started."
"Wonderful. My favorite kind."
⁂
The ritual hall lay beneath the manor's oldest wing, reached through a stair Rose hadn't known existed until Lucien led them to it, stone worn smooth by feet that had walked this path for far longer than any of them had been alive. The air changed as they descended, growing cold in a way that had nothing to do with temperature, a cold that settled behind the sternum rather than on the skin.
They heard Isolde before they saw her, her voice carrying up the stairwell with the particular calm of someone who had waited a very long time and was in no hurry now that the waiting was finally over.
"You should not have come, Rose. But I confess I hoped you would. It's so much more satisfying to finish something in front of an audience who understands exactly what they're losing."
The hall opened into a chamber vast enough to swallow the sound of their footsteps entirely, candles ringing a circle carved deep into the stone floor, the same hollow drop-of-blood symbol from the chapel repeated at its center, larger here, waiting. Noah stood bound at its heart, gagged, his eyes finding Rose's the instant she stepped into the light, wide and furious and frightened all at once.
"Let him go," Rose said. "Whatever this is, it doesn't need to be him."
"It has always needed to be one of you." Isolde stood at the circle's edge, unhurried, a blade already resting in her open palm. "Your mother understood that, in the end. She simply made the wrong choice about which of her children she was willing to spend."
Rose moved. She didn't decide to; her body simply carried her forward, and she made it three steps before the chamber's far door swung open and four of Isolde's guards emerged with Mara's hands already zip tied in front of her, a fifth man's arm locked around her throat hard enough to still whatever fight she'd offered on the way down.
"Mara." Rose's voice cracked on the name.
"They have my mother," Mara said, and her voice was steadier than her face, the voice of someone reciting something she had already decided she would say no matter what it cost her. "They've had her since this morning. Isolde's men, waiting at the house. I'm sorry, Rose. I'm so sorry. I didn't have a choice."
"Everyone always has a choice," Isolde said pleasantly. "Some of them are simply more expensive than others. Miss Quinn's family has been very useful in reminding her of the price of hers."
Rose felt something in her chest go cold and still, the particular stillness of watching a trusted structure reveal a crack she hadn't known was there. "What do they want you to do."
Mara's eyes went, briefly, to a lever set into the wall behind her, half hidden by shadow, and back to Rose's face, and something passed across her expression too fast for the guards flanking her to catch it, though Rose caught it perfectly, twelve years of friendship having taught her exactly what Mara's face looked like right before she did something reckless.
"They want me to hold this," Mara said, and pulled the lever with both bound hands before anyone could stop her.
⁂
The circle's outer seal cracked with a sound like ice breaking underfoot, a fissure of dark light racing along the carved groove and snuffing three of the ringed candles at once. Isolde's composure slipped for the first time since they'd entered the chamber, her head snapping toward the broken seal with an expression closer to genuine alarm than anything Rose had yet seen on her.
"You foolish girl," Isolde said. "Do you have any idea what you've just done?"
"Bought them a few minutes," Mara said, breathless, already twisting against the guard's grip while his attention was divided. "Hopefully enough."
It was enough. In the confusion, Lucien moved faster than his wound should have allowed, closing the distance to the nearest guard and putting him down with the same ruthless economy Rose had seen in the study three nights of blood ago, and Rose was already at the circle's edge, working at the ropes binding Noah's wrists with hands that would not stop shaking.
"You do not understand what you are interfering with," Isolde said, and her voice had changed, something older moving beneath the words, patience finally fraying at its very last edge. "You think the Hollow King is my creature. My weapon, summoned to serve House Draeven's ambitions. It never was."
"Then what is it," Rose said, not looking up from the ropes, Noah's pulse hammering under her fingers.
"It is every daughter your family and mine ever gave to this ritual and called sacrifice instead of murder. Every son. Every voice that screamed in this chamber and was told afterward that it had died for something greater than itself." Isolde's eyes, when Rose finally looked up, held something that might once, centuries ago, have been grief, buried now under so much else that it barely registered as anything human at all. "It is not a god. It never was a god. It is simply what two hundred years of hunger becomes when no one ever lets it rest."
The last rope gave. Rose pulled Noah free, and for one suspended second she believed, entirely, that they had won, that the broken seal and the freed hostage and Mara's ragged breathing beside her added up to an ending she could carry all four of them out of alive.
Then the remaining candles went out together, all at once, and the cold that had lived behind Rose's sternum since the top of the stairs surged forward and poured, without warning, without ceremony, into her brother's open, screaming mouth.
⁂
Noah's back arched. His eyes, when they opened again a heartbeat later, were no longer entirely his own, black bleeding into the whites of them like ink dropped in water, and the voice that came out of his throat belonged to something that had been waiting far longer than twelve years to be given a body that wasn't already broken from the inside.
"Rose," it said, using her brother's mouth, her brother's ruined, familiar voice, and smiled with an expression Noah's face had never once made in his life. "You found me. How thoughtful."
Rose did not move. Could not. Behind her she heard Lucien say her name, low and urgent, and Mara's breath catch, and Isolde, of all of them, take a single step backward, the first true fear Rose had ever seen cross the older woman's face.
Whatever stood in front of Rose now, wearing her brother's body like a coat pulled on in the dark, did not blink. It only tilted its head, studying her the way something ancient studies the last unfamiliar thing standing between it and everything it has wanted for two hundred years.
"Let's finish what your mother started," it said, and took a slow, unhurried step forward.