“Someone so mad to get back their lost love that they founded a cult, killed more than a dozen people, created that cave at the convergence, etched that poem on the wall, created a Portal to the ocean . . . ?” Livvy sounded dubious.

“I would do it,” Dru said, “if it was someone I really loved. It might not even have been a girlfriend—maybe a mother or a sister or whatever. I mean, you’d do it for Emma, right, Jules? If she died?”

The black horror that was the thought of Emma dying rose against the backs of Julian’s eyes. He said, “Don’t be morbid, Dru,” in a voice that sounded very distant to his own ears.

“Julian?” Emma said. “Are you all right?”

Thankfully he didn’t need to answer. A solemn voice spoke from the doorway. “Dru is right,” Tavvy said.

He hadn’t gone to sleep after all. He stood by the door, wide-eyed, brown hair tousled. He had always been small for his age, and his eyes were big blue-green saucers in his pale face. He was holding something behind his back.

“Tavvy,” Julian said. “Tavs, what have you got there?”

Tavvy drew his hand from behind his back. He was carrying a book—a child’s book, oversize, with an illustrated cover. The title was printed in gold foil. A Treasury of Tales for Nephilim.

A Shadowhunter children’s book. There were such things, though not many of them. The printing presses in Idris were small.

“Where did you get that?” Emma asked, honestly curious. She’d had something like it as a child, but it had been lost with many of her parents’ things in the chaos after the war.

“Great-Aunt Marjorie gave it to me,” Tavvy said. “I like most of the stories. The one about the first parabatai is good, but some of them are sad and scary, like the one about Tobias Herondale. And the one about Lady Midnight is the saddest.”

“Lady what?” said Cristina, leaning forward.

“Midnight,” said Tavvy. “Like the theater you went to. I heard Mark say the rhyme and I just remembered I read it before.”

“You read it before?” Mark echoed incredulously. “When did you see that faerie rhyme, Octavian?”

Tavvy opened the book. “There was a Shadowhunter lady,” he said. “She fell in love with someone she wasn’t supposed to be in love with. Her parents trapped her in an iron castle, and he couldn’t get in. She died of sadness, so the man who loved her went to the King of the faeries and asked if there was a way to bring her back. He said there was a rhyme.

‘First the flame and then the flood:

In the end, it’s Blackthorn blood.

Seek thou to forget what’s past

First thirteen and then the last.

Search not the book of angels gray,

Red or white will lead you far astray.

To regain what you have lost,

Find the black book at any cost.’”

“So what happened?” said Emma. “To the man who went to Faerie?”

“He ate and drank faerie food,” said Tavvy. “He was trapped there. The legend is that the sound of the waves crashing on the beach is his cries for her to return.”

Julian exhaled. “How did we not find this?”

“Because it’s a children’s book,” said Emma. “It wouldn’t have been in the library.”

“That’s dumb,” said Tavvy serenely. “It’s a good book.”

“But why?” Julian said. “Why Blackthorn blood?”

“Because she was a Blackthorn,” said Tavvy. “Lady Midnight. They called her that because she had long black hair, but she had the same eyes as the rest of us. Look.”

He turned the book around to show a haunting illustration. A woman whose jet-black hair spilled over her shoulders reached out for the retreating figure of a man, her eyes wide—and blue-green as the sea.

Livvy gave a little gasp, reaching for the book. Hesitantly, Tavvy let her have it.

“Don’t tear the pages,” he warned.

“So this is the full rhyme,” she said. “This is what’s written on the bodies.”

“It’s instructions,” Mark said. “If the rhyme is a true faerie rhyme, then for the right person, it is a clear list of instructions. How to bring back the dead—not just any dead, but her. This Blackthorn woman.”

“Thirteen,” said Emma. Despite her exhaustion, her heart was racing with excitement. She met Cristina’s eyes across the room.

“Yes,” Cristina breathed. “What Sterling said—after we caught him, after he’d killed the girl. He said she was the thirteenth.”

Emma said, “‘First thirteen and then the last.’ He’s killed thirteen. He’s got one last one to go and then he’s done. He’ll have enough magic to bring back Lady Midnight.”

“So there’ll be one more,” said Julian. “One that might be different from the last.”

“There must be more instructions than this,” said Ty. “No one could figure out exactly how to complete this spell just from this rhyme.” He looked around, a flicker of uncertainty in his gray eyes. The look he got very rarely, but sometimes, when he thought that there was something in the world that everyone understood but him. “Could they?”