“What does that mean?” my dad asked.

Emil rolled his eyes. “The best-case scenario is that we’ll be existing in a reality different from our own. The worst case—and the most likely one, if you’ve done any research on the subject—is that you’ll create a paradox with the power to destroy the entire known universe.”

“So?”

“So?!” Emil roared. “So I’m saying that you cannot change history, Contreras! Under absolutely no circumstances!”

“But if we can’t change history,” I said, “then the Iamoi…”

“Who are the Iamoi?” Dad interrupted.

“The people here. The ones who brought you here. The ancient Martians.”

“Well, what about them?”

“They wanted to use the time postern to fix their planet,” I said. “So that the atmosphere wouldn’t… you know.”

“That’s impossible,” Emil said firmly. “They cannot be allowed to alter history any more than the three of us. The stability of the universe depends on it.”

“But Emil, we can’t just leave them here to die!”

“Look, kid. I don’t like it any more than you do.” Emil’s voice softened, almost imperceptibly. “But that doesn’t change the fact that this planet was a barren wasteland when we got here. History says they died, so they have to die.”

I stared down at my feet, my ears ringing. I couldn’t let them die. All the people I’d met here, everyone in the citidomes—everyone here in Elytherios. Eos and Marin, Eliin, Corin and Gios, who just escaped from the geroi, were just starting a new life. The people and the plants and the animals—the gurzas—everyone…

…Nadin.

“We don’t really know what history says, Emil,” I said slowly.

He stared at me. “What are you talking about? Of course we do. My team found the evidence here back in the thirties. Relics from their civilization were everywhere. But the planet was dead, and they were gone.”

“Gone,” I repeated. I looked across the longhouse to Corin and Gios, curled up together in the small guest bed, seemingly asleep. “But where did they go? Maybe they didn’t die. Maybe they just… left.”

“Yeah, but where would they have gone?” my dad scoffed. “Venus?”

“He’s right, as much as I hate to admit it,” said Emil. “There’s no evidence of life anywhere else in the solar system besides Earth, Isaak.”

“And Mars in our time,” I said.

“Exactly. In our time…” Emil trailed off as the meaning of my words hit him.

“Maybe it’s not a question of where the Iamoi went,” I said, folding my arms. “Maybe it’s when. What if they came forward?”

Emil nodded his head slowly.

To our time.

Chapter 34

I found Isaak on the edge of the village, where the gurza pens were located. The morning air was chilly and damp—water droplets from last night’s rain beaded on leaves, and small puddles dotted the worn-dirt track.