One of the last things Rector had said before Briar had been thrown out of the orphanage was, “Look, I bet you a dollar he’ll be out again in ten hours. He has to be. The mask won’t protect him any longer than that, and if he doesn’t find his way to safety, he knows to turn around and come out. You’ve got to wait just a little bit longer. Wait until later tonight, and if he doesn’t come back—then worry about him. He’s not going to die in there, he’s not.”

As she walked away from the orphanage in the dark, drizzling rain, Briar wanted to scream, but she needed the energy to walk. She was exhausted from the worry and rage, and she tried to tell herself that Zeke was prepared.

He hadn’t just climbed the wall and dropped down into the city center, filled with hordes of staggering rotters or roving gangs of criminals. He’d taken precautions. He’d taken supplies. There was always a chance he’d be all right, wasn’t there? Ten hours of time in a mask, and if he didn’t find safety he’d turn around and leave. He wasn’t stupid enough to stay. If he could find his way in, he could find his way out.

The entrance he’d used was down by the ocean, by the water-runoff pits, almost hidden by the battered rocks that shielded the drainage way from the pounding of the surf. It had never occurred to Briar that the old sewage lines might still go all the way up, underneath, and into the city. They’d been part of the underground system that collapsed and was later gated up just in case. But Rector had insisted that the remnant population on the other side had cleared the debris that the Boneshaker had left in its wake, that the gate could be opened with less trouble than it looked.

Ten hours ought to be up by nine o’clock, give or take.

Briar made up her mind to wait it out. It wouldn’t do her any good to go home—she’d only worry herself into a frenzy—and it wouldn’t be a good idea to go after him, not yet. If she went in now, there was a fair chance she’d get inside just as he was getting out, and then they’d miss one another and she still wouldn’t know what had become of him.

No, Rector had been right. The only thing to do was wait. There wasn’t so much time left, anyway—only a few hours.

It was plenty of time to hike out to the other edge of the sound and crawl over the rocks, around the thigh-deep tidal pools and past the jagged crags of cliff that hid the abandoned runoff system from the settlements on the Outskirts.

Night had settled down hard and wet, but Briar was still dressed for work, and wearing boots that were tough enough to protect her feet and flexible enough to let her toes feel their way over the rocks. The tide was out—and thank God for that—but the ocean spray still came in on the wind. She was nearly soaked by the time she rounded the last uneven strip of sand and stone and saw the seaweed-draped mechanisms that once had lifted and lowered the pipes out of the ocean.

And there, buried partly by the accumulated years of gravel, shells, and driftwood, lay the cracked brick cylinder that led back under the city streets.

Bleached by the ocean and the rain, worn by storms and battered by incoming waves, the tube was decrepit. It looked like it might collapse if Briar touched it; but when she leaned a hand against it and pushed, it did not move or settle.

She ducked her head underneath the overhang and let the lantern lead her. It still had oil enough for many hours, and she wasn’t worried about anything short of drowning or a downpour putting it out. But inside the coal-black extra-night of the tube’s interior, its glow felt weak and small. The sphere of light cast by the flame only traveled a few feet.

Briar listened as hard as she could, straining to hear anything other than the faint rush of water coming and going and the incessant drip of mist and rain slipping through where the bricks had broken.

This was as close to the city as she’d been since before Zeke was born.

How far was it? Half a mile at most, though surely it would feel longer and more strenuous, doubled over in a crouch and hunkering uphill in the darkness. Briar tried to imagine her son, lantern in one hand and gun in the other. Would he hold the gun? Or would he holster it?

Did he even know how to use it, if he needed to?

She doubted it. So perhaps he’d brought it to trade—and that was smart, she thought. If his grandfather was a folk hero, then small articles of clothing, personal effects, things of that ilk—they’d be valuable enough to buy information, perhaps.

Farther inside the tunnel, she found a patch of moss-covered wall, that was more dry than not, and she sat down. With the back of her hand she rubbed a spot on the bricks. She put the lantern there and wiggled it until she was sure it would stay upright. She leaned back, trying not to feel the chill and damp of the curved wall through her coat; and although she was frightened, and angry, and cold, worried to the point of being ill, she toppled into a rough-dreamed doze.

And then she was awake. Hard.

Her head jerked and she knocked the back of her skull against the concave bricks.

She was confused and stunned. She didn’t remember nodding off, so the jolt awake was a double shock. It took her a moment to figure out where she was and what she was doing there, and another to realize that the world was shaking. A clump of bricks rattled loose and dropped beside her, almost shattering the lantern.

Briar grabbed it and jerked it into her hand before another patch of shaken stone collapsed on it.

Inside the tunnel the echo was deafening, and the sound of crumbling bricks and falling bits of wall sounded like a war being waged inside a jar.

“No, no, no,” she swore and struggled. “Not now. Not now, dear God, not now.”

Earthquakes were common enough, but bad ones weren’t so frequent; and there, inside that narrow, low space of the old sewage system it was hard to gauge the ferocity of this one.

Briar stumbled out of the tunnel and back into the night, and she was shocked to see how close the tide had crept up to her waiting place. She didn’t have a watch, but she must’ve been asleep for several hours and it must be after midnight.

“Zeke?” she yelled, just in case he was inside and trying to find his way out. “Zeke!” she screamed over the rumbling roar of the shifting sands and the shaking coastline.

Nothing answered but the heavy splashes of shattered waves, jostled out of alignment and dropped onto shore. The tunnel wobbled. Briar wouldn’t have believed that anything so big could wobble as easily and lightly as a child’s toy, but it did, and it crinkled down upon itself—and upon the vintage apparatus that had once held it up and steady.

Together the bulk of it swayed and dropped, folding flat as suddenly as a house of cards.

A plume of dust rose, only to be squashed by the ambient moisture.

Briar stood stunned. Her legs adjusted with the rolling earth and she stayed upright; and she tried to tell herself a thousand and one good things that would keep her from panicking.

She thought, Thank God I’m outside, because she’d been in a bad quake once or twice before and it was far more terrifying when the ceiling threatened to drop, and she whispered frantically, “Zeke wasn’t in there. He didn’t come out yet, or he would’ve seen me. He wasn’t in the tunnel when it fell; he wasn’t in the tunnel when it fell.”

This meant that he was still inside, somewhere—either dead or safe.

If she didn’t believe he was safe, she would have started crying, and crying wasn’t going to get her anywhere. Zeke was inside the city and now he was stuck there.

Now it was not a matter of waiting.

Now it was a matter of rescue.

And there was no way under anymore, so Briar would have to go over.

The sand was still rumbling, but it was starting to settle, and she didn’t have time to wait for a perfect path. While the rocks clacked faintly together and the low, ugly buildings of the Outskirts rattled in their foundations, she jammed her hat back harder on her head, hoisted her lantern, and began to climb the mudflats.

Two ways past the wall, over and under—that’s what Rector had said.

Under wouldn’t work. Over would have to suffice.

Perhaps the wall could be climbed, but it couldn’t be climbed by Briar. Perhaps the wall had a secret ladder or a hidden set of stairs, but if that were the case then Zeke would’ve gone that way instead of ducking underground.

Over could only mean one thing: an airship.

Traders who made their way out to the coast came over the mountains when they could. It was dangerous, yes—the air currents were unpredictable and the altitude made breathing a dreadful chore; but scaling the passes on foot was deadly and time-consuming, and it required wagons or pack animals that must be maintained and protected. Airships were not a perfect solution, but to certain entrepreneurs, they looked much, much better than the alternative. But not at this time of year.

February meant frigid rain on the coast. Over the mountains there would be snow, and storms, and astounding gusts of air that could bat a zeppelin like a kitten with a leaf.

The only airships flying in February were run by smugglers. And as soon as Briar realized this, something else became clear: No legitimate businesspeople would ever bring a valuable airship over the Seattle wall—not so close to the acidic, corrosive Blight that pooled within it.

But now she knew something else about the toxic gas. It was valuable.

Chemists needed the gas to make lemon sap. The gas came from inside the city. Airships went over—or past—the wall on a regular basis, even during the worst parts of the year. And just like that, two obvious thoughts collided in her head, leading to an equally obvious conclusion and, finally, to a logical course of action.

A secondary tremor followed the initial quake, but it passed quickly. As soon as the land was stable again, Briar Wilkes began to run.

On the way home she passed debris in the street and people crying or shouting at each other, standing on the cobblestones in their nightclothes. Here and there, something that had fallen over had caught fire. Off in the distance, the clanging chimes of makeshift fire brigades were sounding as the blocks awakened into disarray one by one.

No one noticed or recognized Briar as she dashed, lantern in hand, up the steep hills and around the wide places where big things had fallen and blocked the way. The quake hadn’t felt so bad to her, down on the beach, but the earth was funny sometimes and it moved inconsistently. It hadn’t been nearly so bad as the…