It’s one of the more sensible suggestions, but it’s still too risky. Not having the bikes could mean the difference between life and death. We need to keep hold of them as long as we possibly can.

“Hey, look!” Charlie suddenly cries, pointing ahead.

We ride over to where he was pointing and see animal tracks leading down into crater. If we follow in their footsteps, we’re bound to find a safe way down. It looks like a pack of them walk this route regularly, at least enough to have worn a wide groove into the mountainside. But I look at the others, unsure.

“They might be predators,” I say.

Molly raises a cocksure eyebrow. “Last time I checked, we were the predators,” she says.

I can’t help but smile at her fighting spirit. She’s right. Whatever animals made those tracks, we’re stronger, better, and fiercer than them.

“Okay,” I say. “Let’s do this.”

I lead the way down the perilous path. We don’t use the motors, instead letting gravity do the work. Any way we can save gas now we’ll have to take. Plus, if we’re quiet enough, we won’t draw attention to ourselves to whatever predators are lurking in the bottom of the crater.

Bree holds onto me tightly, tense as I maneuver down the steep incline. Bits of rock tumble from beneath my tires, making my heart fly into my mouth. She’s gripping so hard it’s starting to irritate the wounds on my chest and back.

After a tense ten minutes, we finally make it into the crater. As soon as I get on level land, an eerie feeling comes over me. My spine tingles as I get that undeniable sensation that we’re being watched.

We race across the trough of the crater then reach the steep wall at the other side. There’s no sign of a path back up. I curse under my breath.

“We need to search on foot,” I say. “There’s not enough gas to keep riding back and forth.”

As I start scanning the crater’s edge, it occurs to me that the only way we’re getting the bikes back up is by pushing. Even if we do find a path we can follow, it’s going to be back-breaking work getting back out of here.

“I think I’ve found something!” Molly calls.

We all go over and see her peering into a hole, five feet in diameter, dug into the side of the crater. It’s clearly been made by an animal of some sort.

“Do you think it’s a burrow?” I ask.

“I guess so,” Molly says. “Pretty big burrow.”