While we rode, Nadin told me everything she could remember about growing up on Iamos—living in the geroi’s shadows—which turned out to be more than she’d thought she could do without the System. She seemed to be feeling better every day, which was a huge relief. And in turn, I told her as much as I dared about Mars and Tierra Nueva. When we got too tired for long conversations, we’d play vocab games: she’d tell me a word in her language, and I’d tell her the English equivalent. If I couldn’t think of something in English, there was almost always something in Spanish, or Greek, or even Olmec. It was really weird how much like Earth languages Iamoan was—way more than it should be if there were no connection. Root words from one language, sentence structure from another… It got me thinking about what Emil had said about “Atlanteans.” Whether people from Iamos had colonized Earth or vice-versa, there was an indisputable connection.

I’d lost track of how long we’d been riding the morning we reached the wide, yawning mouth of the caves, opening out to the surface. We must have been slowly ascending for quite some time, but I’d never noticed. The labyrinth of tunnels had turned me around so much, I didn’t know right from left or up from down.

“We’re going to need oxygen,” Nadin said, peering out over the landscape before us. We’d emerged at the bottom of a deep canyon. Spindly hoodoos rose from the ground around us, rocky fingers soaring high above our heads to touch the thinning sky. Water had worn the shapes into the rock—it must have carved the tunnels, too—but there wasn’t a drop to be seen now.

Nadin watched me steadily as I fished the breathing apparatus out of my pack and fiddled with it, trying to figure out which tube went where. “I hope we won’t have to be outside for too long,” she said. “I worry about you getting exposure poisoning.”

I snorted. “I doubt it could be worse than the sunburn I got in Veracruz when I was eleven.”

She came over, turning the tube contraption rightside-up in my hands. “I just—your skin is so pale, Isaak.” She had that tone in her voice, the one she always used whenever she talked about my appearance. Like she felt sorry for me for being so weird-looking. As if it didn’t occur to her that the Iamoi looked as strange to me as I did to them. Every time she did it, I felt smaller, more self-conscious—more like I didn’t belong here. Like I didn’t already know that.