Oh my God, thought Etta. No wonder Ironwood had been willing to sacrifice his sons and grandson in the search for it. This was the ultimate prize. The trump card of travelers. If his control wasn’t already complete, it would be once he had it in hand. All people, in all ages, could be affected by whatever Ironwood had planned.

Did this mean that the passages weren’t a natural phenomenon that travelers had found and tentatively stepped through centuries ago? They’d been made by the ancestors of these families for their personal use? No wonder there were years without passages, and that so many passages were uncharted; they must have predated when the families began to record the destinations, or they had simply been forgotten altogether.

Or, some passages were secret, created for one particular family’s use alone.

“How do the Thorns fit into this?” Nicholas asked.

The notes of the symphony of lives, desires, and revenge suddenly swelled into a chorus of generations, blasting through Etta’s mind. She already knew the answer to his question. “They’re united in wanting to create passages to the past, to return to what they all see as the original timeline, to restore the centuries and years that orphaned them when Ironwood began to bend the timeline to suit his needs.”

Which wouldn’t be the future she had grown up in: days in the park, lessons with Alice, tea with her mom…For a moment, Etta wasn’t sure which was more terrifying: if Ironwood moved forward into the future, or if the Thorns interfered with the past.

“And those who were lost to them,” Alice added. “To save them.”

The way I want to save you. Etta pressed her fingers against her mouth, trying to seal in the whirlwind of sudden uncertainty whipping through her. How is what I want to do any different than what they want to do? Why does Alice deserve to live more than their loved ones?

No—she couldn’t think about it. Alice deserved to live. She didn’t deserve to die, not the way she had.

“They wouldn’t dare,” Nicholas said. She could tell he was trying to avoid looking at her, even as he added, “We cannot save the dead. We cannot even warn them, should we cross paths with them.”

“Only if you follow the rules,” Alice pointed out. “The rules Ironwood established when he rose to power. He destroyed everything, including our way of life.”

More secrets. More to agonize over. More reasons to find the astrolabe as soon as they possibly could. Etta rubbed at the spot between her eyes that had begun to pound in time with her heart. Just keep going. Stopping to think about this too hard would only keep her locked in a cycle of doubt, and she couldn’t afford to be overwhelmed just then. She needed to take things as they came. Her plan would stay the same: Find the astrolabe. Save her mom. Save Alice. Escape Ironwood if they had to.

“I wish it could be the way it was, back when the families flourished and balanced out each other’s powers,” Alice said. “The professor and my father used to talk about it very wistfully. Each family had a proper role, and they alternated them every few decades to ensure no family undermined another and the timeline remained stable.”

“What kind of roles?” Etta asked, curious.

“Record-keepers, financiers, and shifters—that last one entailed correcting any changes to the timeline and checking on the stability of the passages themselves,” Alice explained. “And, of course, one family would hold trials and enforce punishments for breaking the rules—the enforcers.”

“That was ages ago,” Nicholas said dismissively. “Corruption unraveled it rather neatly. My understanding is that it only worked well for a few hundred years, back when the ‘families’ were still mere alliances and clans.”

“Alliances?” Etta repeated. “What do you mean?”

“Did your mother never tell you about our own history?” Alice asked.

She shook her head, trying to beat back the frustration. “It’s…complicated.”

“Ah, well,” Alice said. “No bother. While it’s generally accepted we all come from a common ancestor with the ability, the families today originally existed as alliances between many separate families that united together under banners—the trees we now use as our family names—against their rivals and enemies. That was another time of huge conflict; everyone was trying to claim centuries and territories to control. It was mostly resolved through treaties and the establishment of the system of roles and laws. You can still see the evidence of how widespread their numbers used to be in the diversity within the remaining members of the families today.”

Nicholas flicked his gaze back onto the street below. He shifted again, and now all Etta could see was the long curve of his spine, the strong width of his shoulders, and his left fingers as they tapped against the muscle of his right arm.

“Enough history; it hardly matters now. Ask her the question that brought us here,” he said, a note of impatience in his voice.

Etta turned to Alice with an apologetic look, but she didn’t seem bothered.

“Mom left me a series of clues to find it,” she said. “In a coded letter.”

“A letter that can only be read when a key—a symbol—is placed over it, showing which words are meant to be read?” Alice said with a knowing smile. “We all used to exchange messages that way.”

Etta felt the hair rise on her arms. It was a connection, however thin, to a larger family she’d never known. “We think the next riddle—the clue—is meant to lead us to a passage near the Elgin Marbles, but we’re not sure where to find them in this year. I thought you might know, since your father works for the museum…?”