They are marching.

Mud squelches under their feet and sucks at the soles of their boots, and the air is damp but free. She never thought she'd feel it from the air alone, in how it feels to fill her lungs, or the caress of wind on her cheeks, fingers of it combing her hair into a wild mess, tendrils escaping from her braid to tickle her neck.

It's November, at least that's what she thinks, and the Italian mountainsides are slippery with the beginnings of winter. There's a persistent drizzle, and sometimes it pours, the days melting into each other in the haze. A soldier's life is the march. Keep moving forward. Keep pressing in. Don't ever stop. Don't ever give up.

The company is a mess, all of them really; Zola's compound has taken its toll, and she can see it in the worn and weary faces, in the slouch of shoulders and the fractions of seconds between each step. There are less of them too, a fact that hangs heavy around them, a blanket of quiet grief. But they are moving, the war machine chugging along, surviving, and in that movement, there's hope.

Hope is a powerful thing, Elsa knows; it can sustain a person to points far beyond simple human endurance. She glances behind her at the parade of soldiers, and sees their eyes fixed ahead, following the chapped leather jacket and bounce of red braids under a stolen helmet; Anna, their hero, their savoir when it seemed like all hope had been lost.

Elsa watches her out of the corner of her eye. Anna's steps are sure, shoulders square and defiant, head held high. Her posture has always been rigid, drawn up like an angry cat, trying to appear bigger, stronger. It falls more naturally to her now – whatever she's let them do to her has lengthened her legs, broadened her hips and shoulders. Before, Anna would get winded climbing the castle steps. Now she can march for hours without breaking a sweat, a gun nestled comfortably in the crook of her arm, and her shield strapped to her back.

Against the bleak greys and greens of the forest, the bright golden crocus on a field of purple almost glows. Watching it bounce through the trees, Elsa feels a wash of homesickness, and swallows hard around the lump in her throat. It threatens to take her breath away, the incongruity of Anna being here, her sweet and tiny sister. It was supposed to be one of life's little ironies, that the delicate nature that haunted her in some way every season (asthma, pneumonia, influenza – they're all Anna's ghosts) was the thing that should have spared her from this, the terrible, grinding wretchedness of war.

She's spent more nights bedside than she cares to count, holding Anna's boney hand under a pile of quilts, bathing her forehead with cool water and watching as she struggled to breathe. It has always been impossible to hinder her spirit however, and that, at least, Elsa can still plainly see: the set of her shoulders, the steady beat of her feet on the ground, expression protective and determined and, although she is not smiling, alight with purpose and satisfaction.

Anna never could stand the idea of the world passing her by, of a life sheltered, of what she felt was a privilege she didn't deserve.

"You're going, and you're a princess too," Anna says, arms crossed tightly. "So you can't tell me it's because of my title Elsa; I know it's not. I know you don't think I can do it, but –"

"That's not it. Someone has to stay, Anna. Arendelle needs someone here too." Anna rolls her eyes, mouth pinched tight in a scowl, but lets the lie pass without comment.

"People are laying down their lives, Elsa. I've got no right to do any less than that."

Elsa sighs, pulling the pack onto her shoulder and straightening her hat, deliberately avoiding the anger and hurt radiating out of Anna's expression.

"Just…don't do anything stupid until I get back, okay?"

"How can I," Anna mutters, "when you're taking it all with you?"

"Punk."

"Jerk."

Elsa turns and salutes, watching for the familiar fondness to creep back into Anna's face before slipping out the castle gates. She'll be safe there at least, behind the stone walls and infantry, behind the circlet in her hair and the wheeze in her lungs. No one can hurt her here.

Anna glances at her then and catches her eye, falling in step beside her, and Elsa can't help but keep her lips from twisting into a wry grin – she's done it anyway, the little punk. Princess Anna. Out to save the world.

Under her feet, the terrain is growing rocky and pitches upward. They march on, the whole lot of them quiet except for the white noise of cloth on cloth, and the occasional soft clatter of metal. Anna falls back a little, no doubt to check on someone, and Elsa draws another full breath and marvels privately at the easy, controlled nature of it. She should be breathing harder now – they are climbing mountains on foot, after all – but the burn in her thighs is negligible and her lungs are cool; it's disconcerting after weeks of feverish shaking and shuddering, scraggly breaths and she wonders, not for the first time, just what they'd done, what perversion they'd pumped her with on that table.

More disconcerting is that she can't decide if she minds. Elsa has never been frail before, has never felt broken and weak in body or mind. Her exposure to these things has always been secondhand, through Anna, indomitable spirit betrayed by some twisted fact of nature. To be on the other side, dependent and helpless, agency stripped away and future handed to a madman in his sickening mountain laboratory – she shudders, and shoves the memories down deep, slamming them into the earth. What's done is done. She's stronger now for certain, and if the cold air and the exertion don't exact their normal cost…so much the better for keeping up with her sister, a fire that won't go out, but still needs someone to mind.

Up ahead there's a flash of white and red that jostles her out of her memories, and a gasp catches unbidden in her throat. It's their camp, slowly emerging before them, revealing tents and tanks that blend seamlessly into the trees, men appearing like ghosts when they turn, pale faces like candle lights in a dark room.

Behind her a whoop and a roar as the scene unfolds to the marching 107th, a cheer rising and carrying them the last quarter mile up the hill, through the risen gate, into the heart of camp. Anna takes her position in the front and Elsa follows half a step behind, not quite able to smile when Anna looks for her over her shoulder, checking to see that they're together still.

Everyone talks at once, and it's more noise that she's heard in days: men and women clamoring to pat Anna on the back, to tell the others the story of their escape, of the factory, the man with the red sideburns. In the middle of the chaos Elsa watches quietly as a tall blonde pushes his way into the circle and although she can't hear what Anna says to him, something shines in her eyes when he speaks.

Other conversations flow, nameless commentary in the buzz of activity.

"Did you see her with that shield?"

"I couldn't believe it, myself."

"I thought we were going to die there."

"Perfect soldier – a fighting machine."

"Super serum, I hear, something unnatural – "

Soldier. Unnatural. Elsa hears the word spoken aloud and it's all it takes for her heart to finally break; it's unnatural for Anna to be here, in the middle of war, the one person she swore to protect, who was never supposed to be brought into this mire of pain and loss and violence.

"Let's hear it for Princess Anna!" She shouts, voice cracking, and uses the enormous cheer that erupts throughout the camp as a cover to slip into an empty tent.

In the semi darkness, her tears freeze on her cheeks.