The train he'd crawled beneath had just arrived—that is, its engine faced the platform—but the other train, on his right, was preparing to leave Stropping, and Chang dashed alongside, toward its steaming engine. Without looking back he dove beneath it, scrambling out the other side.

The row of track before him was empty. Chang ran at an angle toward the next train over, painted yellow. He considered doubling around—back to the terminal—or climbing into the train through a window, just to get out of view. But what he needed more was distance. Another twenty yards and he dove under again. On the other side of the yellow train, Chang began to sprint: the train beyond it was in motion, leaving Stropping, its distant front end disappearing into the black tunnels at the station's edge. He glanced over his shoulder— no dragoons.

He reached the train just as its final car swept by. He leapt between the tracks proper, running hard to catch up. The train was gaining speed but so was Chang. His gloved fingers just brushed the rear rail. He looked up to see a figure in the caboose's doorway, wrapped in a hooded black cloak. It was his assailant from the train compartment in Karthe. The man's arm lashed down, a blue spike in his hand. Chang let go before the blow could land and nearly stumbled onto his face. The man stared malevolently at Chang as the train disappeared into the tunnel, his hood opened by the wind. Or maybe that was wrong—maybe he had wanted Cardinal Chang to see his face. Chang bent over, gasping for breath, hands on his knees, as any number of nagging questions began to fall into place.

Francis Xonck was still alive.

SOME DISTANCE behind him, but still closer than he would have liked, a determined pair of dragoons emerged from under the yellow train. Chang broke into a ragged run, following Xonck's train into the dark tunnel. At the very least it would serve as a place to turn and set his own ambush. With any luck, the dragoons would simply give up once they saw him go in—as well they ought to, for the tunnels were insanely dangerous, with tracks crossing each other without any warning and trains screaming out of nowhere from every direction. He'd no desire to enter it himself, and only hoped the passage of Xonck's train would keep these particular tracks clear for at least the time it took to lose the dragoons.

But the tunnel was farther away than it seemed. By the time he reached it, Chang was winded and the darkness echoed with the sounds of other trains. What was worse, the dragoons had not stopped. Instead, the ones in front had paused, allowing the rest to catch up— some ten men in all, sabers out, forming a line between the tracks. Chang spat out another curse and pulled off his glasses, stuffing them into the inner pocket of his coat. He could barely see a thing. He held his stick out before him to find the tunnel's wall, hoping for an alcove to hide in. Instead, he tripped over a half-buried stretch of unused track and fell to his knees. He groped for his stick and looked back, blinking. The line of dragoons raced directly toward him, moving faster than Chang had anticipated. He found the stick and plunged into the darkness, landing hard on the tar-soaked stones. A train roared past—inches away, it seemed, though he knew this was but the speed and violence of its passage. In the doorway of its final car stood a conductor with a lantern, illuminating for a teasingly brief instant the vaulted tunnel where Chang crouched.

One line of tracks veered into a deeper side tunnel. It was the sort of place that might be a trap—even the best ambush would not catch Aspiche and all of his men—but Chang was drawn to it anyway on the chance of another side exit, and an easy escape. Once he'd stumbled in, however, the side tunnel's isolation became its own difficulty, for the blackness was total. Chang felt his way, knocking with his stick, wasting time. He could hear the dragoons calling to one another and then, shadows playing about the cavern, saw with a sick realization that they had fetched lanterns. They would pick him out like a rat cornered in the pantry.

But the flickers of light at least showed him where to go. He broke into a reckless run as the neglected side cavern echoed with the approach of another train. Yet instead of roaring past, this train broke speed to actually enter the cavern. Knowing there were only seconds before he must be found, Chang sprinted toward the curving cavern wall, the bricks black with soot. The wall was a series of arches, each one penetrated by a set of rail tracks, all fanning out from a central spur. Chang ducked inside the nearest arch and flattened himself against the wall. The cavern had become much brighter, both from the train—now easing its way slowly and backwards into the vast hall—and the dragoons waving their lanterns. Chang retreated farther, and was suddenly surprised to see the lantern light reflecting back. His alcove archway was not empty, but exactly designed to house—as it did now—a detached train car.

He edged between the train car and the filthy wall. The dragoons came nearer. Chang flung himself down and rolled beneath the car. He felt for the cross-braces above and hauled himself up off the ties, wedging his boots to each side and wrapping his arms around the cables. In a matter of seconds his tunnel was bright with lantern light. Chang held his breath. The gravel crunched as two soldiers marched the length of each side of the car. Their light passed by and left him in a momentary shadow. He released the air in his lungs and carefully inhaled. The men came back. They thrust their lanterns beneath the car, but Chang remained suspended just out of view. The light was withdrawn. He heard the soldiers walk on to the next tunnel.

Chang slowly lowered himself onto the bed of rail ties, listening to the sounds in the cavern, feeling the pressure of the wood and gravel against his back, and the cool, foul air of the cavern on his face. What if he merely died where he was? How long until his bones would be discovered? Or would they be taken apart by rats and scattered across the whole of the tunnel?

He peered past his boots. The light in the cavern was moving again. Divested of its cars, the engine had reversed direction back toward the station proper. In its wake came the smaller bobbing glows of the individual dragoons. Chang relaxed on the wooden ties—he would wait another few minutes before moving—and turned his mind to more useful matters. Francis Xonck was alive. Colonel Aspiche was diseased. There was growing unrest in the city.

In hindsight, it seemed stupid not to have recognized Xonck during their struggle in the train compartment at Karthe, and his reappearance was a reminder that Chang could take nothing for granted when dealing with the Cabal. For all he knew, not a single person had perished aboard the dirigible. But then Chang recalled the severing of Lydia Vandaariff's head and the Prince of Macklenburg's legs, and then Caroline Stearne floating facedown in the rising flood. The servantry always died.

Chang rolled out from under the rail car, brushing at his coat from habit. Barely able to see a thing—but suddenly curious—he walked, one hand against the wall, to the car's far end. Chang patted his hands across the platform, and found a metal ladder welded to its side. He climbed up and felt for a waist-high railing of chain around the platform's edge. He threw a leg over it and ran his hands across the door. It was metal, cold, and lacking any handle.

Chang retraced his way to the car's other end, finding an identical platform, ladder, and flat metal door. He pulled the glove from his right hand and ran it over the cold surface. His fingers found the depression of a key hole.

He fished out a ring of skeleton keys, sifting through them by feel for three particularly heavy and squat specimens he had acquired in trade from a Dutch thief named Rüud, after Chang had secured him a hiding space on a smuggler's ship to Rotterdam. Chang had more than once contemplated discarding them, annoyed by the weight they added to the ring and having only a thief's word as to their value. He brought the first key to bear with the keyhole, but it would not go in. The second key slipped inside, but did not turn. He jiggled it free with some effort and no little irritation. The third key went in—again the fit was tight—and turned to the right. It did not move. With another burst of impatience, Chang turned the key sharply to the left. The lock caught and the key spun a complete circle, rolling the bar free with a muffled clank.