In your world I am ashes, I am ancestors, my memories and hopes and dreams have gone to build the City of Bones. In your world, I am lucky, because I do not have to live in a world without you. But in this world, I am you. I am the twinless twin. So I can tell you this:

When your twin leaves the earth you live on, it never turns the same way again: the weight of their soul is gone, and everything is off balance. The world rocks under your feet like an unquiet sea. I can’t tell you it gets easier. But it does get steadier; you learn how to live with the new rocking of the new earth, the way sailors gain sea legs. You learn. I promise.

I know you’re not exactly the Ty I had in this world, my brilliant, beautiful brother. But I know from Julian that you are beautiful and brilliant too. I know that you are loved. I hope that you are happy. Please be happy. You deserve it so much.

I want to ask if you remember the way we used to whisper words to each other in the dark: star, twin, glass. But I’ll never know your answer. So I’ll whisper to myself as I fold this letter up and slide it into the envelope, hoping against hope it will somehow reach you. I whisper your name, Ty. I whisper the most important thing:

I love you. I love you. I love you.

Livvy

When Kit lowered the letter, the whole world looked a little too sharp and bright, as if he were seeing it through a magnifying glass. His throat hurt. “What—what do you think?”

I love you, I love you, I love you

Let him hear it, let him believe it and let go.

“I think . . .” Ty reached up for the letter and folded it back into his jacket pocket. “I think this isn’t my Livvy. I’m sure she’s a good person, but she isn’t mine.”

Kit sat down, a little suddenly. “What do you mean?”

Ty gazed out at the ocean, at its steady incursion and recession. “My Livvy would want to come back to me. This one didn’t. It would be interesting to meet this Livvy, but it’s probably good that she didn’t come back with Emma and Jules, because then we couldn’t bring back the right Livvy.”

“No,” Kit said. “No, you don’t get it. It’s not that she didn’t want to come back. She’s needed there. I’m sure she would have wanted to be with her family if she could. Imagine having to bear that loss—”

“I don’t want to.” Ty cut him off sharply. “I know she feels bad. I’m really sorry for her. I am.” He had taken a piece of thread from his pocket and was worrying at it with nervous hands. “But that’s not why I brought you the letter. You know what it is?”

“I guess I don’t,” Kit said.

“It’s the last thing we need for the spell,” Ty said. “It’s an object from another dimension.”

Kit felt as if he were on a roller coaster that had suddenly, precipitously, dropped. He was about to say something when Ty made a soft sound of wonder; he tilted his head back as above them flew a black-and-gray horse and a brown one, their hooves trailing gold and silver vapor. They both watched in silence as the horses landed on the grass in front of the Institute.

One of the riders was a familiar woman in a black dress. Diana. The other was Gwyn ap Nudd, leader of the Wild Hunt. They both watched in astonishment as Gwyn dismounted before going to help Diana down.

*

Dru clambered up onto the roof. Ty and Kit were already there, standing disturbingly close to the roof’s edge. She wasn’t surprised; she’d figured out a long time ago that whenever they wanted to talk in private, they disappeared up here, the way Emma and Julian used to when they were younger.

She hadn’t really talked to either of them since the time she’d gone into Ty’s room. She didn’t know what to say. Everyone else in the family—Helen, Mark—was talking about how well Ty was recovering, how strong he was being, how he was holding up in the face of Livvy’s death.

But she had seen his room torn apart and the blood on his pillowcases. It had made her look more closely at him—at how thin he was, and the scrapes across his knuckles.

After their father had died, Ty had gone through a phase of biting at his own hands. He would wake up in the night having gnawed the skin over his knuckles. She guessed he was doing that again, and that was why there was blood on his pillows. Helen and Mark couldn’t recognize it; they hadn’t been there years ago. Livvy would have known. Julian would have known, but he had only just gotten home. And besides, talking to anyone about it seemed like a betrayal of Ty.

The story of Thule haunted her, too—a world in which Ty was dead. In which she herself was missing. In which the Blackthorns were no longer a family. A world where Sebastian Morgenstern had ruled. Even the name Ash haunted her, as if she’d heard it before, though she had no memory of having done so. The idea of Thule was a dark nightmare, reminding her of the fragility of the bonds that held her to her family. The last thing she wanted to do was upset Ty.

And so she’d avoided him, and Kit by consequence since they were always together. They didn’t own the roof, though. She stomped over to where they were standing, making plenty of noise so she wouldn’t surprise them.

They didn’t seem bothered to see her. “Gwyn and Diana are here,” said Kit. When he’d come to them, he had looked a bit pale, as if he’d spent most of his time indoors and at night markets. Now he had color—the beginnings of a tan and flushed cheeks. He looked more like Jace, especially as his hair had grown out and started to curl.

“I know.” She joined them at the roof’s edge. “They’re going to Idris. They’re going to get the water from Lake Lyn.”

She filled them in quickly, pleased to be the one who had news for a change. Kieran had come out of the Institute and was walking across the grass toward Diana and Gwyn. His back was very straight, the sun bright on his blue-black hair.

Kieran inclined his head to Diana and turned to Gwyn. Kieran had changed, Dru thought. She remembered the first time she’d seen him, bloody and furious and bitterly angry at the world. She had regarded him as an enemy of Mark, of all of them.

She had seen different sides of him since then. He had fought alongside them. He had watched bad movies with her. She thought of him complaining about his love life the night before, and laughing, and looked down at him now: Gwyn had laid a hand on his shoulder and was nodding, clear respect in his gestures.

People were made up of all sorts of different bits, Dru thought. Funny bits and romantic bits and selfish bits and brave bits. Sometimes you saw only a few of them. Maybe it was when you saw them all that you realized you knew someone really well.

She wondered if there would ever be anyone besides her family that she knew like that.

“We should go downstairs,” Ty said, his gray eyes curious. “Find out what’s going on.”

He headed for the trapdoor that led to the stairs. Kit had just started to follow him when Drusilla tapped him on the shoulder.

Kit turned to look at her. “What is it?”

“Ty,” she said in a low voice. Dru glanced over at her brother automatically as she said his name; he’d already disappeared down the steps. “I want to talk to you about him, but not with anyone else around, and you have to promise not to tell him. Can you promise?”

*

“Have a good watch,” Jace said, ruffling Clary’s hair. Diana and Gwyn had departed for Idris. Emma had watched them vanish until they were a speck on the horizon, disappearing into the haze of the Los Angeles air. Alec had gone to be with Magnus, and the rest of them had agreed to take turns at patrolling the perimeter of the Institute.

“We need to be alert,” Julian had said. “This message from the Cohort is a loyalty test. They’re going to be watching Institutes to see who races to Alicante to pledge themselves to the fight against Faerie. They know we’ll delay as long as possible”—he gestured at Mark and Helen—“but I wouldn’t put it past them to move on us first.”

“That wouldn’t be very clever,” Mark had said, frowning. “All they have to do is wait, and they can declare us traitors soon enough.”

“They’re not that smart,” Julian had agreed grimly. “Vicious, but not smart.”

“Unfortunately, Manuel is pretty smart,” said Emma, and though everyone had looked grimmer than ever, no one had disagreed.

Clary and Emma had the second watch after Jace and Helen; Helen had already gone inside to check on Aline, and Emma was trying to look off into the distance while Clary and Jace kissed and made cutesy noises at each other.

“I hope everything’s all right in Alicante,” she said eventually, more to determine if they were still kissing than anything else.

“It can’t be,” said Jace, breaking away from Clary. “They all think I’m dead. There had better be a mourning parade. We should find out who’s sending flowers.”

Clary rolled her eyes, not without affection. “Maybe Simon or Izzy can make a list. Then when we come back from the dead, we can send them flowers.”

“Women will be in mourning to hear of my passing,” Jace said, bounding up the steps. “Garments will be rent. Rent, I tell you.”

“You’re taken,” Clary called up at him. “It’s not like you’re a single dead hero.”