Livvy was in the training room with Dru. Emma could hear their muffled voices through the floor.

She wanted Cristina. She wanted the one other person who knew how she felt about Julian, so she could cry in Cristina’s arms and Cristina could tell her things were going to be all right, and that she was doing the right thing.

Though whether Cristina would ever really think that what she was doing was right, Emma wasn’t sure.

But she knew in her heart it was necessary.

She heard the click of the doorknob turning and closed her eyes. She couldn’t stop seeing Julian’s face as she’d turned away from him.

Jules, she thought. If only you didn’t believe in me, this wouldn’t be necessary.

“Emma?” Mark’s voice. He hovered in the doorway, very human-looking in a white henley shirt and jeans. “I just got your message. You wanted to talk?”

Emma stood up and smoothed down the dress she’d changed into. A pretty one, with yellow flowers on a brown background. “I need a favor.”

His pale eyebrows went up. “Favors are no light thing to faeries.”

“They are no light thing to Shadowhunters, either.” She squared her shoulders. “You said you owed me. For taking care of Julian. For saving his life. You said you would do anything.”

Mark crossed his arms over his chest. She could see black runes on his skin again: at his collar, at his wrists. His skin was already browner than it had been, and there was more muscle on him, now that he was eating. Shadowhunters put it on fast.

“Please continue, then,” he said. “And if it is a favor in my power to grant, I will grant it.”

“If Julian asks—” She steadied her voice. “No. Whether he asks or not. I need you to pretend with me that we’re dating. That we’re falling in love.”

Mark’s arms fell to his sides. “What?”

“You heard me,” she said. She wished she could read Mark’s face. If he protested, she knew that she had no way of forcing him. She could never bring herself to do that. She lacked, ironically, Julian’s ruthlessness.

“I know it seems strange,” she began.

“It seems very strange,” said Mark. “If you want Julian to think you have a boyfriend, why not ask Cameron Ashdown?”

If you and Mark ever . . . I don’t think I could come back from that.

“It has to be you,” she said.

“Anyone would be your boyfriend. You’re a beautiful girl. You don’t need someone to lie.”

“This isn’t for my ego,” Emma snapped. “And I don’t want a boyfriend. I want the lie.”

“You want me to lie just to Julian, or to everyone?” Mark said. His hand was at his throat, tapping against the pulse there. Looking, perhaps, for his elf-bolt necklace, which Emma only now realized was missing.

“I suppose everyone will have to believe it,” Emma said reluctantly. “We can’t ask them all to lie to Julian.”

“No,” Mark said, and his mouth twitched up at the corner. “That would be impractical.”

“If you’re not going to do it, tell me,” Emma said. “Or tell me what I can say to convince you. This isn’t for me, Mark, this is for Julian. This could well save his life. I can’t tell you more than that. I have to ask you to trust me. I’ve protected him all these years. This—this is part of that.”

The sun was setting. The room was suffused with a reddish light. It cast a rosy glow over Mark’s hair and skin. Emma remembered her twelve-year-old self, how she’d thought Mark was handsome. It hadn’t gone so far as a crush, but she could see another past for herself, one where Mark wasn’t taken from them. One where he’d been there, and so she’d fallen in love with him and not his brother. One where she’d been Julian’s parabatai and married to his brother, and they’d been in each other’s lives, bound permanently in every way people could be bound, and it would have been everything they should have wanted.

“You want me to tell him, tell everyone, that we are falling in love,” he said. “Not that we are in love already?”

She flushed. “It needs to be believable.”

“There is much that you are not telling me.” His eyes were bright. He was looking less human and more faerie now, she thought, sizing up the situation, positioning himself within the careful dance of deception. “I assume you will want everyone to know we have kissed. Perhaps done more.”

She nodded. She could definitely feel her cheeks burning.

“I swear to you, I’ll explain as much as I can,” she said, “if you agree. And I swear it could save Julian’s life. I hate to ask you to lie, but—”

“But for the ones you love, you’d do anything,” he said, and she had no answer to that. He was definitely smiling now, his mouth curved in amusement. She couldn’t quite tell if it was human amusement or the amusement of Faerie, which thrived on chaos. “I can see why you chose me. I am here, and close, and it would have been easy for us to begin a relationship. We are neither of us attached to someone else. And you are, as I said, a beautiful girl, and hopefully you don’t find me hideous.”

“No,” Emma said. Relief and a thousand other emotions sang through her veins. “Not hideous.”