“She’s been under constant observation,” said the doctor. “We don’t leave their side for a second in the days after birth, and we record everything that happens. Nobody’s given her anything—just general antibiotics and some milk from her mother.”

“It’s airborne,” said Heron.

Calix finally arrived, gritting her teeth as she hopped toward them. “What’s airborne?”

Samm looked at Heron, slowly realizing what she meant. “Nine Partials have been living in the hospital for a month,” he said. “Ten, since I’m here more often than not. We’ve been injecting the pheromone directly to the bloodstream because that’s the way Vale did it, but it’s a pheromone—it’s designed to be transmitted through the air. Now that you’re living with us twenty-four hours a day, you’re breathing it in, and it’s just . . . everywhere.”

Calix looked at the data screen, then the baby, then back at Samm. “How many of us are going?”

“Going where?”

“To East Meadow,” said Calix. “This is the answer; we have to tell them.”

“We need Samm if we’re going to keep this whole pheromone incubator working,” said Laura.

“Gorman will stay,” said Calix, “and others. Most of them still can’t make the journey.”

“None of you can,” said Heron. “The Badlands will kill you.”

“It’s worth the risk,” said Calix.

Samm shook his head. “It’s too dangerous—”

“You’ll get to see Kira again,” said Calix.

Samm fell silent.

Calix’s eyes were hard. “If this system can work, if Partials and humans can live together, side by side, we can save the other humans, and who knows—maybe the Partials too. Gorman and his team are still alive, even if we don’t know why.” She looked down, just for a moment. “And we can save Kira, too. This is what she came here for.”

Samm breathed deep, trying to think of something to say. He looked at Laura. “She’s right.”

“I know she is,” said Laura. “If there really are more humans out there, we have to do what we can for them.”

“I don’t know if I’ll be able to come back,” said Samm.

“We,” said Calix fiercely. “I’m going with you.”

“Not with that leg,” said Samm.

“You’ll have to shoot me again to stop me.”

Heron fingered the butt of her semiautomatic. “Same leg, or the other one this time?”

“I’m the best wilderness explorer in the Preserve,” said Calix hotly, “even with a bad leg. Frankly, I don’t think you can make it without me.”