Patrick, Alex, and I rose again, bringing our noses level with the sill. The Hosts finished wagging their heads and then broke apart, branching off into the neighboring streets, their faces lowered as usual.

I exhaled, and everyone else, reading our expressions, seemed to as well.

“Well,” Dr. Chatterjee said, “let’s get to the day, then.”

Logistics consumed the morning. The lookouts rotated, reporting back to Ben. A few of the kids took a shift in the cafeteria. Dr. Chatterjee told them to burn through the perishables first, so they served up runny eggs, cartons of milk, and OJ. I fed Cassius and took him out to the flower bed by the sheltered picnic area so he could go to the bathroom. In the gym Patrick cranked open the casement windows, letting the stale air out. The fresh breeze was a relief, what with the hundred or so bodies in close proximity. Alex turned on the TV, which still showed business as usual elsewhere in the world. Dr. Chatterjee continued to check the carbon monoxide detector at intervals, jotting the “unidentified particulate” readings on the dry-erase board.

Patrick walked over and stared at the board. I came up behind him and looked at the readings over his shoulder. They hadn’t dropped at all. In fact, they hadn’t even varied, the percentage remaining dead steady since Chatterjee had first started gathering data yesterday. My stomach roiled.

“You okay?” I asked.

“It’s only been a day,” Patrick said. “The spores have to dissipate at some point.”

Finally he turned, tried for a casual smile. He didn’t say what we were both thinking: Yeah, but will they be gone six days from now?

By the edge of the bleachers, JoJo gave a cry of delight. She crawled under the risers and retrieved—of all things—a Frisbee. She called out to her brother, and they started tossing the disk back and forth. Even here, even now, kids were kids.

A movement at my side broke me from my thoughts, and I glanced over. Alex had drawn level with me. Eyeing the readings, she took in a shaky breath.

She looked over at me, her expression changing. Then she started jogging toward the bleachers.

“Alexandra,” Patrick said. “Hang on.”

But she hopped up on the first bench. “Hey!” she called out, careful not to yell too loud, mindful of the open windows. “Everyone listen up.”

She waited a moment as the others stopped what they were doing.

“I don’t know about you guys,” she said, “but I don’t want to just wait around here and do nothing.”

“What do you propose, then?” Dr. Chatterjee asked.

Alex gestured at the TV, showing a fake-tanned weather reporter gesturing at a map. “We have to get outside the infection zone.”