“What’s that sound?” he asked.

Zeke answered, “See those tubes? Sticking up through the air, and up over the Blight layer?”

“I think so.”

“They’re air tubes, leading down to pump stations. Chinamen work the air rooms, mostly—they use coal and big engines to suck the clean air down, so we can breathe it when we’re underneath.”

“Except when the ceiling caves in.”

“Except for that, yeah.”

Rector might’ve asked more questions, but somewhere nearby a moan rose up—forlorn and raspy and wet around the edges.

The boys all froze. Their eyes jerked back and forth, exchanging silent questions and answers. Houjin said, “You wanted to see a rotter, didn’t you, Rector?”

“I never said I wanted to. I just said I hadn’t.”

Another deep, sad groan called out. This one received an answer.

“That’s them,” Zeke whispered. “Down below. Don’t worry too hard. All these buildings are sealed on the ground floor. They can’t get inside.”

“You sound pretty sure of that.”

Houjin said, “He’s right. These buildings get checked all the time, the ones with the bridges and seals. Yaozu doesn’t want leaks any more than the Doornails do—and he’s got more men working for him. He maintains the place.”

Zeke went to the nearest window and hung out of it, turning his neck this way and that to get the best view through his visor. “I don’t see them, but they sound pretty close.”

“Not too close, I hope.” Rector scratched at the back of his hand, but that only made it itch more. He scratched harder, every draw of his dirty fingernails ecstasy and misery.

Zeke looked back over his shoulder and saw him. “Stop doing that. You’ll make it worse.”

“I already figured that out.”

“Then why are you still doing it?”

“I can’t stop.”

Houjin sighed. “We have to get you some gloves.”

“Can you tell where it’s coming from? Listen…” Zeke said, and they all stopped talking.

At first, the only sounds they heard were the filtered hiss of their own breathing and the scraping of Rector’s nails against his skin.

But outside, the mournful, sickly, wordless cries continued.

“Let’s go see if we can find them,” Zeke suggested.

“Do we have to?”

Houjin said, “If we don’t know where they are, we can’t avoid them.”

“I thought we weren’t going down within grabbing distance.”

Zeke hemmed and hawed as he went to the other corner window. “We have to get down and cross one street. There aren’t any bridges into the tower—it’s too far away from the nearest buildings.”

“You two can really try a man’s patience, you know that? You tell me no more stairs, and then there are ladders. You tell me we’re staying out of reach, and then you admit we’re headed into the road where rotters can chase us all they like.”

“Goddamn, Wreck. I don’t know when you got so fussy, but it don’t look good on you.”

“Catch me sometime when I haven’t been in bed sick for a week.”

“You were in bed hurt, for four days,” Houjin corrected.

Rector would’ve spit if he hadn’t been wearing that miserable mask. He fumed instead. “Neither one of you is worth a damn as a guide.”

“Getting around inside the wall ain’t like walking across the Outskirts, Wreck. And I still don’t see the rotters,” Zeke said. “Maybe we should—” He stopped. And he whispered, “Do you hear that?”

“The rotters?” Rector asked.

Zeke shushed them, then held out his hands to imply that Houjin and Rector ought to do likewise.

Houjin came up beside Zeke and pressed his back against the wall. He peered out the window, then told Rector, “Yaozu’s guys. You want to avoid them.”

“But Yaozu invited me.”

“Yes,” Zeke nodded. “But those fellows are trouble, some of them. Maybe they’ll believe us if we say we’re on a mission from their boss, or maybe they’ll think we’re dumb kids who’re up to no good. We’ll tell Yaozu we ran into some rotters and had to take the long way around. He keeps an eye on where they cluster, so as long as we’re telling the truth, he won’t get too mad about it.”

Rector didn’t like any of this, but he could hardly object, so he followed Zeke’s lead. He settled down on his hands and knees in case someone his height could be spotted through that big broken window.

All three boys hid, but peeked over the edge of the sill down at the street below.

To the west of their hiding spot was the empty shell of a building without a roof. Or, to be more precise, the roof had fallen down inside it and now served as a very uneven, none-too-attractive floor. This floor had a large hole at one end, though where this hole disappeared to was anybody’s guess.

Houjin kept his voice low. “That place used to be called McKinnen’s; it was a dry goods store. It was too far gone to shore up and save. Not enough structure to seal it or make it useful.”

“Someone thinks it’s useful,” Rector muttered back.

“Looks like it,” Zeke said, almost too loudly. “What’s going on down there?”

They craned their necks, still trying to keep from being seen. Their shoulders knocked together and their knees jockeyed for position. Fragments of ancient broken glass scattered under their grasping, brushing fingers.

In the ruins of McKinnen’s, no more than thirty yards away, two men were backing up toward the hole in the former roof. Each man held a rectangular metal shield that looked as though it had been pounded out of tin. With these shields, the men pushed, knocked, and otherwise pressed four staggering, unsteady men away from themselves and the hole.

“Rotters!” Zeke said in a voice too high pitched to call a whisper, and not loud enough to call an exclamation.

“Fresh ones!” Houjin said back. His eyebrows crowded close together behind the visor. “Real fresh.”

“What are those two guys doing?” Rector asked. “The ones with those … shields, or whatever they are.”

Houjin breathed, “I don’t know…” as if it were something he didn’t often say. “It’s like they’re … they’re herding those rotters away from that hole. You know what, I bet you it goes down to the underground. They’re just trying to get away from the rotters. I think that’s all.”

Rector adjusted his position so he could scratch at his hands some more. “Why don’t they shoot them?”

It was a good question. Neither of the boys had an answer.

Zeke smacked Rector’s fingers away from one another in a vain attempt to keep him from scratching, then said, “The fellows with the metal plates have masks on. The other guys don’t, but they haven’t been rotters more than an hour. Look at ’em—their clothes ain’t even torn yet. Maybe they had some kind of accident.”

With worry dripping from every word, Houjin said, “The cave-in. It must’ve been worse than we thought. They were poisoned by the air downstairs.”

Rector said, “That don’t explain what they’re doing in the middle of that old shop.”

One rotter fell out of the ruins and into the street, and another was kicked away by the shield bearers. One at a time, the two masked men backed down into the hole—using their metal plates to hold the new rotters at bay—and disappeared. With a loud, fumbling clank and crash, a door was slammed into place from somewhere below.

The hole vanished, and the rotters were left to mill about, groaning and griping.

They wandered away in a small, sad pack, and were gone.

Rector, Houjin, and Zeke stared after them until the shambling men could no longer be seen through the fog, then they waited a little longer, until they could no longer hear the things, either. When the coast was clear, Zeke let out a nervous laugh and pulled himself to his feet. “That’s just about the damnedest thing I ever seen!”

Houjin shook his head in disbelief, not disagreement, but Rector didn’t get it. “What was weird about it? Rotters are weird, sure. But I thought people down here … got used to them. Those two fellows in masks, they were used to them.”

Zeke said, “People who are used to ’em don’t shove them around with big metal plates. They shoot them in the head and call it a day.”

“It’s true,” Houjin assured Rector. “That … that was … exactly what you said. Weird.” Then he fell silent.

Zeke didn’t seem to notice, and Rector didn’t want to push. He’d gotten enough bad news already, and there was still a bogeyman to meet. “Weird or not, we’ve got an appointment, don’t we? Get me down to see this guy.”

“Right,” Houjin said firmly. He looked glad to be given a new train of thought. “Not much farther.”

“You keep saying that.”

“It keeps being true. Down some more stairs, across the street, and into the Smith Tower.”

Zeke chimed in, “And then it’s a straight shot to the Station.”

This time, Rector’s guides were as good as their word, though the truth of the matter didn’t make crossing the street any less nerve-racking given the blind corners, the soup-thick fog, and the fresh knowledge of rotters in the area. But everyone stayed quiet and all heads were kept down, and soon they were back underground beneath the tall, white tower.

In the meantime, Rector concentrated on putting one foot in front of the other. It took more focus than it should have, but Rector wasn’t merely tired, and he wasn’t merely battered. He was also dogged by the old yearning tugs of sap, and it made him cranky. Now that he was up and around, just thinking about it made his head ache and swell. He felt the exaggerated sensation of his cheeks inflating, stretching the gas-mask straps and squeezing his skull. He tasted that peculiar yellow stink in the back of his throat, down past his tongue. He experienced the ghost-pains of his simmering blood, wanting to be seared like lightning.