New Yorkers are pretty unflappable as a group, and the motley crew in our car was no exception. An elderly Asian woman held the hand of an adorable little boy in a blue peacoat, who spoke to her calmly in English, though she spoke to him in something else, maybe Chinese? Next to her a frazzled-looking mother was trying to keep her two children from breaking off in opposite directions after her bag of groceries had fallen to the floor. Her apples scattered across the car like billiard balls. But no one cried. No one panicked. Not until the lights went out.

There was silence at first, then noise. People talking, a child crying. The car wasn't completely dark-the emergency lights were on in the adjacent cars, just not in ours.

"This stuff happens all the time," Jamie said. His face was painted in a faint, eerie glow. "They'll figure it out."

A burst of static startled Daniel-I felt him jump against my shoulder. Someone's cell phone buzzed with a text. And then a stranger said my name.

"Mara Dyer?"

The owner of the voice was a twentysomething girl with gauges in her ears, a hoop in her nose, and a bushel of wild, curly hair. She held a book with a leafy green tree on the cover, title obscured, and a cell phone in the other. "Who is Mara Dyer?"

I felt Daniel's and Jamie's eyes boring into each side of my face. The stale air seemed to press in on me, slowing my thoughts. "Uh, me?" I said, before Jamie shushed me.

Everyone in the car stared as Curly Girl walked over to me and handed me her phone. "Someone's texting you."

"I don't know you," I said, pointing out the obvious.

"And I don't know you. But the person texting me doesn't seem to care." She gestured with the phone. "See for yourself."

I tried to, but realized that my arms were in the iron grips of my brother and Jamie.

"This is bad news," Daniel said. "Bad news."

I shook them off and took the phone from the girl.

I HAVE WHAT YOU WANT.

Below that was a picture of Noah. I couldn't see where he was and didn't know what he was doing; it was just a close-up of his face. But it was Noah to the life. And there was a newspaper next to him with today's date.

"Can I have my phone back now?" Curly Girl asked. I ignored her.

"Ask who it is," Jamie said.

"Like he's going to answer?" Daniel replied.

"How do you know it's a he?" Jamie asked.

Daniel rolled his eyes. "It's a he."

Who is this, I texted back. A few seconds later, the girl's phone pinged again.

DOES IT MATTER? OPEN THE DOOR BETWEEN CARS AND GET OUT. LEAVE YOUR BROTHER AND FRIEND BEHIND SO THEY DON'T GET HURT.

"Trap," Daniel and Jamie said simultaneously.

"Hey," Curly Girl said, clearly annoyed now. "My phone?"

Jamie looked at her and said, "This isn't your phone." Her forehead creased and her eyes glazed over. "You dropped your phone on the tracks."

"I dropped it?" Her voice wavered as she looked back and forth between Jamie and the phone in my hands.

"Yes. Run along now." Jamie gestured at her. "Shoo."

When she walked away, I stood up.

"Oh, come on, Mara," Jamie said.

Daniel was shaking his head as he spoke. "You're not going out there."

"Of course I'm going out there." More static from the speaker, but no lights and no movement still. Daniel and Jamie were right. Obviously right. And I was in no frame of mind to process the picture other than to seize it as proof that Noah was, in fact, alive. I had to make sure he stayed that way. I had to make sure Daniel and Jamie stayed that way too.

"Sister, I love you, and I would do anything for you, but I really do not want to creep around in the bowels of the New York City transit system for you. Please do not make me."

"Not only am I not making you," I said as I reached for the handle of the door between the cars. "I'm not going to let you."

"You're not going to stop me," Daniel said.

Jamie bent over. If he'd had hair, he'd have been pulling it. "Damn it, Mara. We've been here before."

I opened the door and stepped out into the darkness. "True," I said. "And I was fine before."

"I suppose that depends on your definition of 'fine.'"

"Look," I said to Daniel and Jamie, "what's the most terrifying thing you can think of in these tunnels? Rats? Mole people?"

"Evil mastermind hell bent on killing you?" Jamie suggested.

"Wrong. The most terrifying thing in these tunnels is me." I shut the door on both of them and jumped onto the tracks.

The girl's cell phone buzzed in my hand.

WALK TOWARD THE END OF THE TRAIN UNTIL YOU PASS IT. GO TO THE THIRD NICHE WITH A DOOR.

The curved walls seemed to stretch into infinity, but I started walking, following a miniature creek between the tracks that was choked with garbage. Air ruffled papers taped to the graffitied, wet-looking walls. My pulse began to race as I neared the end of the train, but not from fear. I believed what I'd told my brother and Jamie. I believed in myself. I would find Noah, and I would punish whoever had taken him from me.

I passed the first niche, and then the second. But before I came to the third, I heard my name shouted behind me.

"Mara?" Daniel's voice echoed in the tunnel. Panic seized me.

"Wherefore art thou, Mara Dyer?" Jamie's voice this time.

"That means 'why', not 'where,'" I heard my brother say. "Just saying."

"Go back!" I yelled automatically, then cursed myself. Not for giving away my position to my mystery texter but for giving it away to my brother. Marco Polo used to be his favorite game.

Daniel yelled, "No chance! I'm your big brother. It's my job to protect you."

And then a shadow peeled itself from the wall, forming the outline of someone I knew, of the person I'd expected ever since I'd seen that first text. Ever since I'd heard the girl on the subway say my name, really.

"Don't hurt them," I said to Jude, and I meant it. "Please."

"I didn't want to," he replied, and punched me in the face.

49.

BEFORE.

Cambridge, England

THERE WAS NO KNOCK ON the professor's door before it opened, throwing a shaft of dim, gray light into the room.

A girl stood in the doorway, but did not enter. She was half in shadow, but I did not need to see her to know who she was.

The professor lifted a glass of amber liquid to his lips and sipped as he wrote in his notebook. "Come in, Naomi."

Naomi Tate hurried in, bringing the scents of rain and nervousness with her. She shut the door forcefully, rattling the shutters, and a few leaves that had clung to her coat scattered to the scratched wooden floor.

"Bit early to be drinking, Professor?" she said casually, as she shrugged off her coat.

"Perhaps it's a bit late." He continued to write without looking up.

Naomi's hair was damp and wild, and she tied what she could into a messy knot at the nape of her neck as she moved in front of the professor's desk. Fine blond wisps curled around her forehead and temples, framing her face.

That face. With high cheekbones and a long, elegant nose, Naomi was beautiful in a rare, peculiar way, in a way that demands attention. I'd known her for a year and still, I could never quite get used to looking at her.

But there was something different about her today. I shifted in the tufted, battered leather armchair I always sat in, my island amid the chaos that was the professor's Cambridge office, and sniffed the air. The scents in the room were all familiar: old paper mingling with leather and mold; the coriander and musk that was the professor; the paperwhites and cedar that was Naomi. And something else, something- "What can I do for you, Mrs. Shaw?" he asked. He took another slow sip of whiskey.

Mrs. Shaw. She was Mrs. Shaw, now. I kept forgetting. She'd married the grandson of Elliot, whom I last saw at eight years old, throwing books and toys about his room, because he couldn't find the one he wanted. I did not know her husband well, but my impression was that David Shaw was not terribly different.

Naomi refused to answer the professor; she would not fight for his attention. She would make him fight for hers. I loved that about her.

After several seconds, he finally abandoned his notebook and looked up at her. His lips pulled back into a smile. "You're pregnant," he finally said.

A sharp intake of breath. Mine. "How far along?"

I hadn't heard the professor rise from his desk, but he was standing when he spoke. "Early," he said, approaching Naomi with slow, graceful steps. "About two weeks?"

Naomi didn't speak, but she nodded. She rubbed at a knot in the ancient desk with her finger-she was nervous, but grinning madly anyway.

I let out the breath I hadn't realized I was holding. "It's too early," I said to the professor. "She might not be-"

"I am," she said, in a tone that left no room for argument. "I am."

The professor ran a hand over his chin and mouth. Then said, "May I?" He indicated her flat stomach. Naomi nodded.

The professor drew nearer, until he was close enough to touch her. I noticed the way her muscles tightened in apprehension, the way her aqua eyes dropped to the floor as he reached out to her. When he placed his hand low on her belly, Naomi flinched. A tiny movement, one she tried to disguise. If it bothered him, he didn't show it.

"Three fifteen," he said, and withdrew his hand. Naomi relaxed. "What does it mean to you?"

Her cheeks flushed, and she began rubbing at the pockmarked desk again. "The day I conceived, I think. March fifteenth."

"Does David know?" I asked quickly.

Naomi shook her head. "Not yet," she said, and swallowed. She glanced up at the professor. "I wanted to tell you first."

"Thank you." The professor inclined his head. He leaned over his desk and began to write. "For now, I'd prefer you didn't mention it to him. Can you do that, Naomi?"

"Of course," she said, rolling her eyes.

"You'll be having a boy, you know."

All traces of her earlier irritation vanished. A smile lifted the corner of her mouth. "A boy," she repeated, as if saying the word for the first time. "You've seen him?"

The professor hesitated for a moment, then said, "Yes."

"Tell me everything," she said, her face lit with excitement.

"I don't know everything," the professor said, "but I do know he has your smile."

Her hands drifted down to her lower belly. "I can't believe this is really happening."

"It is happening." The professor had counted on this, on her, and I had too. "The boy is destined for greatness. Because of you, he will change the world."

And because of him, Naomi would die. It was a sacrifice she was willing to make. It cost the professor nothing; but I was the one who had convinced her to make it. I needed her child too, and her death was easy to accept when Naomi was just an abstraction, a stranger. But now I knew her, and I was haunted by guilt. I had befriended her, persuaded her, knowing that there was no time line in which she would have this child and live, and over the months, the specter of her someday-death haunted me. I dreamed of her hanging by a rope from the rafters in a stable, her feet bare, her body swinging after the tension in the rope snapped her spine. I dreamed that a shard of glass pierced her chest after in a car accident, and she died choking on her own blood. I dreamed of her murder, her drowning, her being buried alive beneath a collapsing building. I didn't know when it would happen, but I knew that it would.

Before her wedding, I couldn't help but warn her again. She would be a martyr for this child, I told her.

Every gift has its cost, she had said back.

I could see the beginnings of that cost today. There was none of a new mother's emotion in her expression, no awe or wonder, or even love. Instead she looked like a child who'd been told she'd be setting off on a great adventure soon, and she couldn't wait to begin.

She nearly bounced on her heels. "I wish I didn't have to wait nine months to meet him," she said.