The propeller swung, caught, bit. The noisy little radial engine started up, sneezing smoke. The Rusalka rumbled out even as Nina was checking her compass and map. They’d only been in the mountainous region a few weeks, but this was a world different from the summer nights they’d flown at the southern front. Here in the Caucasus the winds could come screaming out between the steep mountain peaks and fling a U-2 into a cliff face in a heartbeat. And if the winds didn’t get you, the heavy, gluelike mists might. Two U-2s had collided in one of those lethal mists last week. Only one survivor.

The lights along the field flickered on, marking a makeshift runway. So close to the front line, Nina could hear the crackle of not-so-distant ground fire and tracer fire, yet as soon as they lifted off there would only be the midnight-blue horizon stretching ahead, the endless blanket of stars. No clouds tonight, just a sliver of moon—a perfect night for flying. Not for sleeping, Nina thought with a wolverine flash of teeth as the Rusalka began to pick up speed under Yelena’s hands. Their target was troop bunkers, every one packed full of German soldiers freshly arrived at the front. “Let’s give the new boys a warm welcome, ladies,” Major Bershanskaia had said in briefing that afternoon. Nina had looked around to see every sestra wearing the same feral grin. No one sleeps tonight.

The U-2’s undercarriage lifted off the crushed grass, and the Rusalka soared. Nina’s heart soared with it—no matter how many dozens of times she’d done this, it was always the same liquid-sweet catch at her throat. She took a moment to savor the icy rush of the air, and then it was back to business. Yelena was waiting.

“East a hair . . . aim for the southwest pass . . .” The Rusalka twitched to each of Nina’s directions as she scanned the surrounding mountains. Some navigators relied on flares, pitching them over the side and setting course by the falling red glow, but Nina scorned flares. Map and compass, moon and stars were enough for her.

The first bombing run always passed in a flash. It was thirty minutes’ flying before reaching the target, but it seemed like only seconds passed before they were descending through a wisp of cloud like silver veiling. “One minute,” Yelena called, leveling out, and Nina went marble still. It was teeth-chatteringly cold up so high, autumn winds biting cruel and sere in the open cockpit, but whenever they lined up for a run, Nina flushed as warm as though she stood before a roaring fire.

The Rusalka hit an updraft, steadied. Then the world fell away into stillness as Yelena cut the engine.

That was the moment Nina loved best, when the U-2’s nose dropped and she began her weightless glide downward. Like a rusalka plunging down into the glassy dark of her lake, Nina thought, webbed fingers catching the currents of the water as Nina’s gloved fingers caught the currents of the air . . . Silent, invisible, undetectable, until far, far too late. Those yawning German soldiers below had no idea what slid toward them out of the night. You’re on our ground now, you stupid little boys, Nina thought. You have your Führer and your Fatherland, but we have the Motherland and she has us.

“Six hundred meters,” Yelena called. Nina poised her hand. A buzzing drone filled the wind as Yelena kicked the engine back to life; they were low enough Nina could see lights below, dark shapes of dugouts, German trucks. The instant they began to rise, Nina flicked the release. Their payload of bombs dropped into the black velvet night, Yelena already veering away from the searchlight that stabbed the sky seconds after the bloom of explosions below. The light hunted for them like a blind white finger, but Yelena had already jinked out of reach, finding the new altitude. Not three minutes behind them the next U-2 would be lining up, Dusia Nosal with her hatred-tautened face relaxing as she dropped her load in turn. And the next, and the next, and by the time every U-2 in the regiment had finished its first run, Nina and Yelena would be back on their second.

“First away,” Yelena called through the interphones, satisfaction in every word.

“Well done, rabbit.”

The Rusalka had barely touched down on the flattened grass before the first wave of ground crew came swarming out to service her. Girls in overalls jogged over with cans of fuel, armorers staggered under the weight of thirty-two-kilo bombs, mechanics crawled over propeller and engine by flashlight. Yelena twisted in her cockpit, reaching a hand back to Nina. “No ground fire,” she said. “But they’ll be wide awake next time.”

Nina shrugged. “We’ve been holed before.” There had been fierce nights on the southern front when the Rusalka had been so peppered by bullets that her linen-covered wings looked like a cheese after the mice got at it, yet she was always ready to fly by the following twilight. “Bullets won’t bring down a U-2 unless they hit both of us. Even then, this bird could probably land herself.” Nina squeezed Yelena’s fingertips, a stand-in for the kiss they couldn’t exchange in public, and swung out of the cockpit to the ground. A pair of armorers hunched over a bomb, one girl holding a flashlight for the other who squatted with gloves clamped between her teeth as she attached the fuse with fingers gone blue-marbled with cold, and Nina veered around them to go make her report inside. Major Bershanskaia always heard the first round of reports herself. “Good, Comrade Lieutenant Markova. Carry on.” Nina saluted, gulped some tea that tasted of engine grease, and hurried back with a cup for Yelena.

“Drink up,” she ordered, stepping onto the wing over the armorer lugging a bomb along on her knees toward the rack. Yelena drained the cup in one gulp, scribbling her signature on the release form a petite mechanic was thrusting under her nose, and in minutes they were circling for takeoff again. Behind them, the mechanics and armorers were already clustered around Dusia’s U-2 like worker bees round a hive queen as Dusia slumped back in her cockpit and her navigator went trotting inside to make her report and bring her pilot some tea . . .

“Let’s break our record tonight,” Nina said as the mechanic gave the prop a swing. “Ten runs?”

“Ten,” Yelena agreed as the engine’s drone rose, and Nina could hear the elation in her voice. By the sixth, seventh, eighth run her voice would be blurry with exhaustion, but for the first few runs everyone was still bright-eyed. Once again the Rusalka leaped up into the diamond-sewn night, heading for the front line.

Will anyone die tonight? Nina wondered. The 588th had already suffered losses. Three just last week in that midair collision . . . But it was no use thinking of tracer fire ripping up through the cockpit, or the spiraling terror of a crash. There was a job to do. The first week of flying back in June, Nina and Yelena had managed four bombing runs per night. Now with the nights getting longer, Nina reckoned ten would be possible. And when the endless white nights of deep winter arrived, the nights when dark fell greedily on the day and gobbled it up like Baba Yaga eating unwary children, who knew what they might accomplish?

“How long has it been?” Yelena wondered on their sixth touchdown, gnawing on the cold biscuit Nina had grabbed inside. “Since we first started on the southern front?”

Nina had to think. The nights blurred together, the days even more. “Three months.”

Yelena gave a jaw-cracking yawn. “Feels longer.”

Those early weeks had felt like being flung into the deepest part of the Old Man with rocks tied to their feet. They took off for the evening’s first run with the fascist line so close that Nina wondered if the airfield would be in German hands by the time they landed. Bombing the rolling columns of German tanks as they advanced, the pilots flew over fields of grain ripe to be harvested and saw flames leap along the golden rows instead of scythes as billows of wheat were converted into billows of fire rather than be left to feed a single German soldier. Black clouds roiled into the sky, and the regiment’s U-2s touched down with smoke-blackened wings and red-eyed pilots to the news that the Fritzes had seized another town, another river, another city, one after another gone under the swastika. Hearing Major Bershanskaia’s grim voice reading aloud from Order No. 227, direct from Moscow: “‘It is time to finish retreating. Not one step back.’”