Ceeron crouched low. “Did you hear that, Emma? You can come out now.”

We waited for the human to climb from Ceeron’s backpack.

But she did not come out.

A second went by. And another.

And still no Emma.

Worry buzzed across my wiring. Emma had seemed fine when she entered Ceeron’s backpack. But what if . . . ?

What if she had been hurt in the fall?

Or during our escape?

What if there was something wrong with her and we did not even know it?

“Emma?” Peering inside Ceeron’s backpack, I spotted her, curled up inside the narrow space, her hands clenching her knees. “What is wrong? Are you injured?”

She shook her head.

“We made it out of the TrainDepot,” I said. “We are safe now. You can leave the backpack.”

But she still did not move.

SkD rolled up beside me. Question marks blinked on its screen. All I could do was shrug.

I turned my attention back to Emma. Her arms were still hugging her knees in the darkness of Ceeron’s backpack.

Like she was hiding inside a metal cave.

When she spoke, her voice was quieter than usual. “Did I tell you about my mom’s job back in the bunker?”

I searched my memory drive. An instant later, I shook my head.

“She was a scientist,” Emma said. “She was always experimenting with ways to make life better in the bunker. New sources of food. Better ways to recycle oxygen and water. That kind of thing.”

I had so many questions. To be exact, 42,285. And at the top of that list:

Why?

Why was she telling me this?

But before I could ask, Emma spoke again.

“In the lab where my mom worked, they had a couple of cages with mice inside. Cute, fuzzy, little mice. When I was little, I loved watching them through the bars of their cage. The way they’d run around. Or nibble on food. Or sleep. Just living their little mousey lives, you know?”

SkD beeped. I glanced at its screen.

I lowered my vocal settings and replied, “I do not know why she is talking about mice.”

Emma continued: “One day, I was in the lab. I must’ve been seven or eight. And I asked my mom, ‘Why do you keep mice in the lab?’ She looked up from her microscope. I could see her thinking for a second. Then she was like, ‘Mice help scientists with their experiments.’ Of course, the first thing I imagined was mice wearing tiny lab coats, fiddling with tiny beakers.” Emma laughed. “Stupid, I know. But I was just a little kid. That’s what popped into my head.”

Her voice echoed faintly against the metal walls.