“What are the weak spots?” Alicia was beside them now. She freed the safety on her rifle and, making an effort to keep quiet, pulled the bolt. Then they heard it: a thump from above.

“They’re on the roof.”

Michael stumbled from the back room. He looked them over, frowning, his eyes blurry with sleep. “What’s going on?” he said, too loudly. Alicia touched a finger to her lips, then pointed urgently to the ceiling.

More sounds of impact came from overhead. In his gut Peter felt it, a soft bomb exploding. The virals were searching for a way in.

Something was scratching at the door.

A thump of flesh on metal, of bone on steel. It was as if the virals were testing it, Peter thought. Gauging its strength before they made a final push. He tightened the stock against his shoulder, ready to fire, just as Amy stepped into his line of vision. Later he would wonder if she’d been in the room all along, hiding in a corner, silently observing. She stepped to the barricade.

“Amy, get back—”

She knelt before the door, placing her palms against it. Her head was bowed, her brow touching the metal. Another thump from the far side, though softer this time, searching. Amy’s shoulders were trembling.

“What’s she doing?”

It was Sara who answered. “I think she’s … crying.”

No one moved. There were no more sounds coming from the far side of the door now. Finally Amy shifted off her knees and stood, facing them all. Her eyes were distant, unfocused; she seemed not to be seeing any of them.

Peter held up a hand. “Don’t wake her.”

While they watched in silence, Amy turned and walked, with the same otherworldly air, to the door to the bedroom, just as Mausami, the last sleeper, emerged. Amy pushed past her without appearing to notice her. The next thing they heard was the squeak of rusted springs as she lay down on her cot.

“What’s going on?” Mausami said. “Why is everybody looking at me like that?”

Peter went to check the window. He pressed his face against the slot. It was as he expected. Nothing was moving outside; the moonlit field was empty.

“I think they’re gone.”

Alicia frowned. “Why would they just leave like that?”

He felt strangely calm; the crisis, he knew, had passed. “Look for yourself.”

Alicia slung her rifle and pressed her eyes to the window, her neck straining as she tried to widen her field of vision through the opening.

“He’s right,” she reported. “There’s nothing out there.” She drew her face away and turned toward Peter, her eyes narrowed. “Like … pets?”

He shook his head, searching for the right word. “Like friends, I think.”

“Will somebody please tell me what’s going on?” Mausami said.

“I wish I knew,” said Peter.