The Shenandoah was so close she could see it now, its engine straining and speeding along, the pistons churning and pumping. She could also see faces-that’s how close it had come-faint but definite, lining the windows in a mirror of the men on the Dreadnought. Men also dashed to and fro along the Rebel engine and its scant number of cars, climbing with the certainty of sailors on masts or cats along cupboard shelves. It was strange and awful, the feeling of pride combined with horror Mercy felt as she kept her eyes on them, tracking one after another like ants on a hill.

While she stared, and while the mountain shadows flickered and flew across the pass and across the trains, a tense pall settled upon the men and women of the Dreadnought. Maybe, Mercy thought, the same moment of hesitance was making the Shenandoah quiet, too. It was one final moment when things might possibly go another way, and the confrontation might end in some other fashion-or never occur at all.

And then, with the sound of a planet exploding, the moment passed and the battle came crashing down upon them.

Mercy could not be certain, but she believed the first blow happened simultaneously, as if both trains’ patience simply exhausted itself, and everyone shot at once-taking a chance on starting something awful, rather than receiving something awful without kicking back.

Or maybe the Dreadnought fired first.

And why shouldn’t it? The Union train had the most to lose, being stuffed with gold and paperwork and soldiers, and being an expensive piece of war machinery to boot. Heavier, slower, and more valuable, the Dreadnought had one primary thing going for it: immense firepower. As Mercy scanned the cars of the Shenandoah, tugged behind one another like sausage links, she saw only one fuel car and only one vehicle that looked remotely prepared to move armaments and artillery. The engine itself was armored and reinforced, yes, but its gunnery lacked the forethought and sophistication of the Dreadnought’s assault-oriented design.

So the Dreadnought’s strategy was simple. It had to be simple, for the options were so strictly limited.

Stay ahead of the Shenandoah. Don’t let it outpace us.

Blow it off the tracks if you can, or if you have to.

Fire.

The nurse would play the moment over and over in her head, on an infinite loop that would surprise her sometimes, startling her out of a reverie or out of her sleep, for the rest of her life.

And she would listen to it, watch it, scrutinize it through the windowpane of her memory and wonder if it mattered. Surely it didn’t matter who fired the first shot, or what small action caused the event to begin. But merely knowing that it might not matter did not make it bother her any less, not at the time and certainly not in retrospect, and it did not keep that moment out of her waking nightmares.

Her terrified and very human reaction was to duck down, to dodge, to lie on the floor and pray.

Ears ringing, she staggered to her feet and tried to hold that position-upright, still crouched, out of the line of fire. But the train was reeling. It rocked on the track even as it hauled itself forward, keeping that pace, not letting the Shenandoah come up too close but throwing everything it had at the other train. The recoil from the engine’s cannon, the unevenness of the track, the gathering clumps of snow that must surely have knocked the balance here and there . . . these things made it hard to stand and hard to concentrate, never mind how the sound of war and windows breaking compressed and reverberated within the steel and cast-iron tubes.

Gunpowder smoke accumulated despite the errant wind, and driving snow collected inside the car-dusting the seats and the corners, and drifting wherever it found a relatively quiet eddy in the raucous, rattling mayhem.

It was hard to breathe and even harder to see, but one of the sharpshooters was sharp-shot, and he tumbled backwards off the seat where he’d braced himself. Mercy ran to his side. She knew the soldier on sight, but didn’t recall his name. His face was surprised, and stuck that way.

Someone shouted. Mercy couldn’t make it out; but someone tripped over the corpse and nearly kicked her in the shoulder, all by accident, all in the calamity of the moment. Sensing a way in which she could be useful, she drove her arms up underneath the dead shooter and man-hauled him backwards across the aisle and against the far wall beneath a window that faced the sheer cliff.

The forward door burst open and Horatio Korman stood framed within it, holding it ajar and fighting with the wind to keep it from flapping him in the face. “Mrs. Lynch!” he hollered.

“Over here!”

“Next car up! Come on now, we need you!”

“Coming!” she said as loud as she could, but no one could have heard her over the din. “I’m coming,” she said again, and even if the ranger hadn’t caught the words, he caught the sentiment. He extended a hand to her, and only then did she realize she was still half crawling in the aisle.

“Hang on,” he told her. He seized one of her wrists and lifted her bodily up, into the doorway, and then he pressed her against the wall to the side of it-outside in the frozen storm of rushing air-as he jammed the door shut behind himself. Together they stood on the place above the couplers, the platform that shifted back and forth as if deliberately designed to keep anyone from standing upon it-while the train was shaking so badly, and snapping like the sharp end of a whip every time a new cannon volley was fired from the engine up front.

“Hang on,” the ranger urged again. He took her hand and placed it on the rail.

She squeezed it, feeling the iron leech a sucking chill up through her gloves. It was a skinny thing, made only to guide, not to support. Certainly it’d never been made to support a wayward passenger under circumstances such as these.

“Hurry. We’re wide open. If they see us, and if they get a shot, they can take us.”

She wanted to believe they wouldn’t-just like before, maybe, when they’d seen a woman on the train, and maybe since they knew Ranger Korman was present . . . maybe they’d know him by his hat and his posture. But then she realized something astonishing: His hat was gone, either blown out into the Utah mountains or stashed someplace in one of the cars, she didn’t know which. His dark hair whipped wildly, with the one white stripe flickering down the middle like a candle’s flame.

“I’m coming,” she said, and the act of opening her mouth to tell him let the winter into her mouth and down her throat. She choked on the words and squinted against the wind, though it cut tears out of her eyes and froze them on her skin.

Blindly she groped for the door-and, still more on her knees than on her feet, she found it. The ranger braced her, using his body to give her as much cover as he could; and when the door opened, they toppled inside together.

Mercy hit the floor hands-first and sorted herself out enough to ask, “Who needs me?” only to see Private Howson holding his hands over some gaping bit of bloody flesh at his throat. “Let me see it,” she commanded, approaching him on hands and knees, and none too steadily even at that.

Something bright and loud exploded very close.

The windows splintered and blew inward. Soldiers screamed with dismay or pain, and the day was bright with a split second of terror and chaos. When it had passed, there was blood-much more blood-and the powder and slivers of glass joined the blowing snow within the passenger car.

“Nurse!” someone cried.

She said, “One at a time!” but she looked over her shoulder anyway, and saw Pierce Tankersly wearing a long slash of red across his forehead and one shoulder, and a shard of glass sticking out of one hand. It was bad, but not as bad as Private Howson’s gushing throat wound, so she gestured and said, “Over there, Mr. Tankersly. Against that wall. Anyone who needs help, against the far wall!”