“Jennifer,” Tom called. “Tell me about … your first day of school.” The dark of the Tombs pressed down. “Jennifer?”

The silence was so loud Tom wanted to cover his ears. But the shackles on his wrists were getting hard to lift. He was weakening, and he knew Jennifer was, too. He’d heard it in her voice the last time they talked. And now she wasn’t answering.

She was sleeping. That was all. She needed to sleep, to slow her body down. It was the best thing for her. It was what he had to believe. Tom lay down in the dirt beside his dry water bucket, eyes squeezed shut though the dark remained the same. Was Sophie being smart? Had she found LeBlanc’s ally, or had LeBlanc found her? Was Sophie dead? Or was she coming for him? And she would get Jennifer, too, wouldn’t she? He wasn’t going without Jennifer, or whatever was left of her.

“Jen?” he called. “Jen!” He was alone with his echo.

Before, he hadn’t wanted his sister to come. Now he only wanted her to hurry.

Sophia came running down the farmhouse stairs. René looked up from the Monde Observateur, while Spear straightened from over a trunk, adjusting his position so his head wouldn’t brush a ceiling beam.

“Sophie. Good,” he said. “We should …”

“I need to see the firelighter,” she said, hands on hips.

“Sophie, I don’t—”

René interrupted. “You are well, Mademoiselle?”

“Yes,” she lied. Orla had stayed with her the night before, rubbing her back until she could stop crying. Then she’d slept like a brick, felt awful for it, and woken up guilty. Cartier was coming to drive a load into Canterbury, so their bags could travel ahead of them to the Sunken City. The luggage had to be on the dusk ferry, the same ferry they would catch themselves at dawn, and now it was nearly highsun and the sitting room was still littered with lists and half-packed boxes and trunks.

But it had occurred to her midcry the night before that all her plans for blowing up the Tombs were based on Spear’s firelighter working as they had discussed. What if it did not work as they had discussed? What if it did? To come out of the Tombs or not, she hardly knew which she wanted anymore. But what she did want was to understand her possibilities. She wanted to know if her scales had tipped.

“I need to see the firelighter,” she repeated.

Orla came through and set down a basket of laundry for packing, shaking her head when Spear turned to René and said dismissively, “Sophie and I have plans to discuss.”

Hot blue eyes met hers, and René inclined his head, a stinging smile in one corner of his mouth. He stood to move away just as Orla passed Sophia at the bottom of the staircase.

“Do something about it, child,” Orla whispered as she brushed by.

“No,” Sophia said. “Wait.” Both men turned their heads, but it was Spear she was speaking to. “I think he needs to see.”

Spear didn’t say anything.

“It would be for the best. Neither one of us will be close by if something goes wrong, or if it doesn’t go off …”

“It will go off, Sophie,” Spear said stiffly.

“I know. But we haven’t gotten this far by not having a plan B, have we?” She planted her feet a little more firmly, listening to Orla continue her trip up the stairs after a long pause to listen. René stood with his shirt untucked and hair undone, hands in pockets, watching Spear, whose practiced expression was impossible to read.

She must have looked a little fierce because Spear did not argue, only said slowly, “Of course, Sophie. If that’s what you want.”

Spear ducked through the open door of his bedroom while Sophia came to the couch and sat. René dropped into his usual chair, neither of them looking at the other. But she could feel him sitting there, like a redheaded, smoldering fire.

Spear came back with his bundle from the night before. They watched as he untied the sacking, and on the low table in front of the couch he set a small wooden box with an odd mechanism attached to its top. On one side was a clock face, painted with simple symbols for the times of the sun and moon, a skinny black pointing finger pivoting out and around from the middle. Spear sat down on the couch next to Sophia, and they all leaned forward. The box made a strange tick, tick, tick in the quiet room.

“You have to make sure it’s wound,” Spear began. “Use this key, here.” He put a blunt-ended key in a hole on the side of the clock, and turned. The clock made a sharp clicking noise above the ticks. “Turn until it’s tight, no more. Then start with the finger pointing to the time that is now.” Spear glanced at Sophia. “You know how the symbols work? Dawn at the bottom, then around to middlesun, highsun, to nethersun, and then dusk, and the same for the moon, middlemoon, highmoon, nethermoon, and then you’re back to dawn …”

Sophia bit her tongue. Of course she knew how time worked.

René was leaning forward, his curiosity on display. “Ancient clocks were marked with numbers,” he said, “but I have never understood how time can be held to a number. Every night it takes a little longer and a little longer for the moon to reach its height, or else a little less and a little less, but a clock makes the same number of ticks each day to get to the marking of highmoon. It cannot be accurate.”

“That’s why clocks will never really work,” Spear said. “Technology can’t keep up with those kinds of changes. It does better with the sun, of course, the sun being more regular, and when the moon is full it’s not too far off. We’re only two or three days out from a full moon, so by the time we get to the city we should be able to go by the times marked, which is good. Another week and we’d be making guesses, especially at night …”

“Well, I think you’re looking at it all wrong,” Sophia said, chin in hand, eyes on the symbols of sun and moon. “I’ve always thought that the Ancients could have used the clock to mark the time of day, instead of marking the time of day on a clock.”

René leaned back. “Tell me what you mean, Mademoiselle.”

“I mean that a clock is precise, divided up into even ticks, right? What if the Ancients used the number of ticks to mark the time of day, instead of the height of the sun or moon? So highmoon could happen here …” She put a finger on the space between middlemoon and highmoon. “… or even here.” She pointed to the area close to nethermoon. “That way highmoon is not the time; highmoon is happening at a different time every night. If you’re counting the ticks as time.”

Spear chuckled. “You mean that two Ancients could agree to meet at highmoon, wait until the clock says it’s highmoon, look up in the sky, and see the moon still rising?”

“Hence the preference for numbers on a clock,” she said, “rather than the symbol for highmoon.”

“That’s mad, Sophie,” Spear said.

René stretched his arms up behind his head. “No,” he said, holding Sophia’s eyes for a moment. “It is brilliant.”

She dropped her gaze back to the clock, so he could not see how ridiculously pleased that comment had made her.

“So, you start by pointing the finger at the time it is now,” Spear said quickly, “and by that I mean the time it really is …” He glanced once at the filmy windows, and moved the finger to just past the full yellow circle, the symbol for highsun. “And then you turn the wheel …” He spun the clock around to show a small, flat wheel on the back of the box, sun and moon symbols also neatly painted. “… and point it to the time you want the machine to work.”

Sophia looked at Spear sidelong, smiling a little, watching him turn the wheel to just past highsun. He really was clever to have made this, and it was obvious that he was enjoying the opportunity to show off the firelighter, whether he had wanted René to see it or not.