“Don’t be silly,” Curly said. “It’s for your own good. Come on out of there.”

Lyra edged into the hall, keeping her hands on the walls, which were studded with nails from which brooms and mops and dustpans were hanging. She couldn’t remember what day it was. The knowledge seemed to have dropped through a hole in her awareness. She couldn’t remember what day yesterday had been, either, or what had happened.

“Follow me.” The nurse put her hand on Lyra’s arm, and Lyra was overwhelmed. It was rare that the nurses touched them unless they had to, in order to take their measurements.‎ Lyra’s knowledge of the nurse’s name had evaporated, too, though she was sure she had known it just a second earlier. What was happening to her? It was as if vomiting had shaken up all the information in her brain, muddled it.‎

Lyra’s eyes were burning and her throat felt raw. When she reached up to wipe her mouth, she was embarrassed to realize she was crying.‎

“It’s normal,” the nurse said. Lyra wasn’t sure what she meant.

It was quicker from here to go through C-Wing, where the male replicas were kept. Nurse Cheryl—the name came back to Lyra suddenly, loosed from the murky place it had been stuck—Nurse Cheryl, nicknamed Curly for her hair, which corkscrewed around her face, buzzed them in. Lyra hung back. In all her years at Haven, she’d only been through C-Wing a few times. She hadn’t forgotten Pepper, and what had happened. She remembered how Pepper had cried when she’d first been told what was happening to her, that she would be a birther, like all those dark-skinned women who came and left on boats and were never seen outside the barracks. Pepper had left fingernail scratches across the skin of her belly and begged for the doctors to get it out.

But two months later, by the time the doctors determined she couldn’t keep it, she was already talking names: Ocean, Sunday, Valium. After Pepper, all the knives in the mess hall were replaced with plastic versions, and the male and female replicas were kept even more strictly apart.

“It’s okay.” Curly gave her a nudge. “Go on. You’re with me.”

It was hotter in C-Wing. Or maybe Lyra was just hot. In the first room they passed she saw a male replica, lying on an examination table with probes attached to his bare chest. She looked away quickly. It smelled different in C-Wing—the same mixture of antiseptic and bleach and human sweat, but deeper somehow.

They took the stairs up to ground level and moved past a series of dorms, lined with cots just like on the girls’ side and mercifully empty. The males who weren’t sick or in testing were likely getting fed in Stew Pot. Despite the standard-issue white sheets and gray blankets, and the plastic under-bed bins, the rooms managed to give an impression of messiness.

They passed into B-Wing, and Curly showed her credentials to two guards on duty. B-Wing was for research and had restricted access. Passed laboratories, dazzling white, illuminated by rows and rows of fluorescent light, where more researchers were working, moving slowly in their gloves and lab coats, hair concealed beneath translucent gray caps, eyes magnified, insect-like, by their goggles. Banks of computers, screens filled with swirling colors, hard metal equipment, words Lyra had heard her whole life without ever knowing what they meant—spectrometry, biometrics, liquid chromatography—beautiful words, words to trip over and fall into.

One time, she had worked up the courage to ask Dr. O’Donnell what they did all day in the research rooms. It didn’t seem possible that all those men and women were there just to perfect the replication process, to keep the birthers from miscarrying so often after the embryo transfer, to keep the replicas from dying so young.

Dr. O’Donnell had hesitated. “They’re studying what makes you sick,” she said at last, speaking slowly, as if she had to carefully handle the words or they would cut her. “They’re studying how it works, and how long it takes, and why.”

“And how to fix it?” Lyra had asked.

Dr. O’Donnell had barely hesitated. “Of course.”

The Box was made of concrete slab, sat several hundred yards away from the main complex, and was enclosed by its own fence. Unlike the rest of Haven, the G-Wing had no windows, and extra security required Nurse Curly to identify herself twice and show her badge to various armed guards who patrolled the perimeter.

Curly left Lyra in the entrance foyer, in front of the elevator that gave access to Sub-One and, supposedly, the concealed subterranean levels. Lyra tried not to look at the doors that led to the ER, where so many replicas died or failed to thrive in the first place. Even the nurses called the G-Wing the Funeral Home or the Graveyard. Lyra wondered whether Lilac Springs was there even now, and how long she had left.

Soon enough, the elevator doors opened and a technician wearing a heavy white lab coat, her hair concealed beneath a cap, arrived to escort Lyra down to see Mr. I. It was, as far as Lyra could tell, the same tech she’d seen the half-dozen or so times she’d been here in the past month. Then again, she had trouble telling them apart, since their faces were so often concealed behind goggles and a mask, and since they never spoke directly to her.

In Sub-One, they walked down a long, windowless hallway filled with doors marked Restricted. But when a researcher slipped out into the hall, Lyra had a brief view of a sanitation room and, beyond it, a long, galley-shaped laboratory in which dozens of researchers were bent over gleaming equipment, dressed in head-to-toe protective clothing and massive headgear that made them look like the pictures of astronauts Lyra had occasionally seen on the nurses’ TV.