There was a green oasis nearby, a dense cluster of trees that seemed at odds with the stripped-down land stretching in every direction. But here and there, as they drew their camels into the city, Etta saw evidence of ravines and what looked like small canals.

Now that they were inside the boundaries of the ruins, and Etta had to crane her neck back to look at the carved reliefs on the columns’ heads, it was easy to imagine the magnificent scope of the city in its prime. Hasan had called it one of the most dazzling stops along the ancient trade routes between east and west, a once carefully cultivated jewel that had fallen into neglect, and then devastation, as new civilizations rose up and the roads redrew themselves. There was an amphitheater and a large, towering building that Etta assumed was some kind of temple, but for the most part, they were weaving through the remnants of the buildings’ foundations. Their footprints.

“Well?” Sophia said, turning her camel sharply to cut off the path of Etta’s. Daisy, as she’d started calling the camel, let out a growl and began to dance around impatiently.

“‘Well,’ what?” Etta asked, adjusting her hood. The sun was at its pinnacle, beating down on the top of her head, reminding Etta she needed to keep drinking the water in her rapidly shrinking goatskin.

“What was the clue? Where are we supposed to find it, now that we’re here?”

Lie to her, Etta thought. You’re already here, you don’t need them, and she won’t change her mind. You can go and search by yourself.…Except, of course, that if they got separated, Sophia might be able to find it first, and Etta would be too far away to stop her.

The last resort, then, Etta thought miserably. The stakes were obvious to her now, and it felt like every other minute she’d been biting back tears of bitter frustration. She couldn’t save herself and her future and save her mom. Last night, she’d lain awake for hours trying to imagine the world Cyrus would try to build and control with the astrolabe. Etta had tried to convince herself that Sophia would be the lesser of two evils. But the truth was, Sophia was like a firework with a lit fuse; it would only be a matter of time before her temper or impatience got the best of her, and her plans exploded around her. Then, the astrolabe would almost certainly find its way back to Ironwood.

“I’ll tell you,” Etta said, “but only in exchange for something.”

Sophia’s brows rose at that. “This silly game again, Linden? Really?”

Etta sat up straighter in her saddle, struggling against the rising tears of frustration. I’m sorry, Mom. I just wanted you to be proud of me.… “You could spend weeks, months, maybe even years searching for it here. I’ll help you, but only if you let me create a passage directly back to my time.”

To her surprise, Sophia seemed to be considering this. “You actually know how to use the damn thing?”

Etta seized on the small, hopeful surprise in the other girl’s voice, and lied. “Yes. It was in my mother’s letter. I’ll show you, but only if I have your word you’ll let me create the passage.”

She wouldn’t need more than a second to smash the astrolabe. Etta only needed to find a way to get it into her hands.

“All right,” Sophia said, holding out her hand to shake. Etta took it, meeting the girl’s gaze evenly. “Now tell me what you know.”

“We think the clue refers to a burial place,” Etta said, hoping she wouldn’t live to regret it. “Some kind of a tomb.”

Sophia blew out a hard gust of air from her nostrils. “Can’t you be more specific?”

Etta narrowed her eyes.

The other girl was all impatience and nerves as she moved toward the guardians, consulting with them in rapid Arabic. Sophia had been in a mood from the moment they left the caravanserai that morning; Etta had dismissed it then as the product of too little sleep and too much saddle soreness, but now that she was watching her again, some worry crept in. Frustration might lead her to do something rash.

More than that, thought Etta. She had been watching the guides, her ears tuned in to what few conversations they had, to see if they’d mention the Thorns again. When she’d tried to suggest that they might leave the guardians, or send them back once the city came into view, Sophia had simply snapped her whip and sent her camel into a trot ahead of Etta’s.

Daisy spat, rearing her head back, grumbling something in her own peculiar language. Etta leaned forward and patted her neck. She knew the feeling.

As Hasan had said, there were still people living on the outskirts of the city, most of them in tents and smaller, more temporary structures that looked like they were made mostly of dried mud. They kept to themselves as their party moved down what once must have been a breathtaking colonnade, but Etta felt their eyes tracking her progress.

“Where are we going?” she asked.

“Fadi claims there is a valley of tombs just beyond the city,” Sophia said stiffly.

“So you do know their names,” Etta muttered, watching the backs of the men’s heads as they rode steadily in front of them, looking a thousand times more at ease on their camels.

“Of course I do,” Sophia snapped. “I’m not as heartless as everyone would make me out to be. Besides, I had to know their names to find them and to pay them, to keep my little adventure—coming after you—away from Grandfather’s ears.”

“It must have been a real novelty,” Etta began coldly, “to make a decision to do something without him ordering it. To actually pull one over on him. It’s nice to have a little freedom, isn’t it? Think of what you could have had if you’d actually taken my advice and left the family behind.”