“Mark,” she breathed, and then paused. “Are you Mark? Faeries weave illusions, don’t they?”

He cocked his head to the side. His blond hair fell across his forehead. She remembered when it had hit his shoulders, as if he were the illustration of a faerie prince in a book. Now it was short, soft and curling. She had given him a modern haircut, and it seemed odd suddenly, out of place in Faerie. “I cannot hear my heart or what it tells me,” he said. “I can only hear the wind.”

It was one of the first things he had ever said to her.

“It is you,” she said, exhaling with relief. “What are you doing? Why aren’t you sleeping? We need to rest, if we are to arrive at the Unseelie Court by moon’s rise.”

“Can’t you hear the music?” he said. It was louder now, the very clear sounds of fiddles and woodwinds, and the sound of dancing, too—laughter, and the stamp of feet. “It’s a revel.”

Cristina’s heart skipped a beat. Faerie revels were things out of legend. The Fair Folk danced to enchanted music, and drank enchanted wine, and sometimes they would dance for days. The food they ate made you delirious or love-struck or mad . . . it could pierce your dreams . . . .

“You should go back to sleep,” Mark said. “Revels can be dangerous.”

“I’ve always wanted to see one.” A surge of rebellion went through her. “I’m going to go closer.”

“Cristina, don’t.” He sounded breathless as she turned and moved down the hill toward the noise. “It’s the music—it’s making you want to dance—”

She whirled around, a curl of black hair sticking to her damp cheek. “You brought us here,” she said, and then she plunged on, toward the music, and it rose up and surrounded her, and she could hear Mark, swearing but following after her.

She reached a field at the foot of the hill and stopped to stare. The field was full of blurred, colorful movement. All around her the music echoed, piercingly sweet.

And everywhere, of course, there were Fair Folk. A troupe of faeries in the center of the dancers, playing their instruments, their heads thrown back, their feet stamping the ground. There were green-skinned wood faeries dancing, with gnarled hands and eyes that glowed yellow as sap. Faeries blue and green and shimmering as water, with hair like transparent netting cascading down to their feet. Beautiful girls with flowers wound through their hair, tied around their waists and throats, whose feet were hooves: pretty boys in ragged clothes with fever-bright eyes who held out their hands as they spun by.

“Come and dance,” they called. “Come and dance, beautiful girl, chica bella, come and dance with us.”

Cristina began to move toward them, toward the music and the dancing. The field was still clouded with fog, carving its streaks of white across the ground and hiding the blue of the sky. The mist glowed as she moved into it, heavy with strange scents: fruit and wine and incense-like smoke.

She began to dance, moving her body to the music’s rhythm. Exhilaration seemed to pour into her with every breath she took in. She was suddenly no longer the girl who had let Diego Rosales fool her not once, but twice, not the girl who followed rules and trusted people until they broke her trust as casually as knocking a glass off a table. No longer the girl who stood back and let her friends be wild and crazy and waited to catch them when they fell. Now she was the one falling.

Hands seized her, spinning her around. Mark. His eyes were flashing. He pulled her up close against him, his arms slipping around her, but his grip was unyielding with anger. “What are you doing, Cristina?” he asked in a low voice. “You know about faeries, you know this is dangerous.”

“That’s why I’m doing it, Mark.” She hadn’t seen him look so furious since Kieran had come riding up to the Institute with Iarlath and Gwyn. She felt a small, secret pulse of excitement inside her chest, that she could make him that angry.

“They hate Shadowhunters here, don’t you remember?” he said.

“They don’t know I’m a Shadowhunter.”

“Believe me,” said Mark, leaning in close so that she could feel his breath, hot, against her ear. “They know.”

“Then they don’t care,” said Cristina. “It’s a revel. I’ve read about these. Faeries lose themselves in the music, like humans. They dance and they forget, just like us.”

Mark’s hands curved around her waist. It was a protective gesture, she told herself. It didn’t mean anything. But her pulse quickened regardless. When Mark had first arrived at the Institute, he’d been stick-thin, hollow-eyed. Now she could feel muscle over his bones, the hard strength of him against her.

“I never asked you,” he said, as they moved among the crowd. They were close to two girls dancing together; both of them had their black hair bound up in elaborate crowns of berries and acorns. They wore dresses of russet and brown, ribbons around their slim throats, and swished their skirts away from Mark and Cristina, laughing at the couple’s clumsiness. Cristina didn’t mind. “Why faeries? Why did you make that the thing you studied?”

“Because of you.” She tilted her head back to look up at him, saw the surprise that passed across his expressive face. The beginning of the gentle curves of wonder at the corners of his mouth. “Because of you, Mark Blackthorn.”

Me? His lips shaped the word.

“I was in my mother’s rose garden when I heard what had happened to you,” she said. “I was only thirteen. The Dark War was ending, and the Cold Peace had been announced. The whole Shadowhunter world knew of your sister’s exile, and that you had been abandoned. My great-uncle came out to tell me about it. My family always used to joke that I was softhearted, that it was easy to make me cry, and he knew I’d been worrying about you—so he told me, he said, ‘Your lost boy will never be found now.’ ”

Mark swallowed. Emotions passed like storm clouds behind his eyes; not for him Julian’s guardedness, his shields. “And did you?”

“Did I what?”

“Did you cry?” he said. They were still moving together, in the dance, but it was almost mechanical now: Cristina had forgotten the steps her feet were taking, she was aware only of Mark breathing, her fingers locked behind Mark’s neck, Mark in her arms.

“I did not cry,” Cristina said. “But I did decide that I would dedicate myself to eradicating the Cold Peace. It was not a fair Law then. It will never be a fair Law.”

His lips parted. “Cristina—”

A voice like doves interrupted them. Soft, feathery, and light, it crooned, “Drinks, madam and sir? Something to cool you after dancing?”

A faerie with a face like a cat’s—furred and whiskered—stood before them in the tatters of an Edwardian suit. He held a gold plate on which were many small glasses containing liquid of different colors: blue, red, and amber.

“Is it enchanted?” Cristina said breathlessly. “Will it give me strange dreams?”

“It will cool your thirst, lady,” said the faerie. “And all I would ask for in return is a smile from your lips.”

Cristina seized up a glass full of amber fluid. It tasted of passionfruit, sweet and tart—she took one swallow, and Mark dashed the glass from her hand. It fell tinkling at their feet, splashing his hand with liquid. He licked the fluid from his skin, glaring at her all the while.