Ella could hear the echoes of the vault door clanging shut through the cave behind her, muted in the still afternoon air.

One of the traders, lean and wiry - Cricket? - was hunched over a concrete-block cooking fire outside, among the rusting vehicles and the portable Vault-Tec cabins. She lifted her hand in greeting as they emerged from the darkness. Ella raised a hand automatically in response.

The sunlight sparkling off the water in the reservoir in front of her was almost painfully bright. She took an unsteady step down the dirt path back towards the city, but her foot skidded on a loose stone. Her power armour's knees locked as she began to slide, and she threw out her arms to try to regain her balance. She skidded to a halt, heart pounding.

Her power armour was suddenly stifling, the air circulating through the ventilation system tepid and thick. She wrenched herself out of her suit into the sunshine, trying to ignore the dull ache in her limbs as she moved. She turned to look at the damaged knee of the suit, the servomotor dangling and the reinforced rubber lining torn almost completely off. The back of her leg throbbed in sympathy as she looked at it, although the jagged bite a molerat had taken out of it had now been healed, the skin now smooth and unblemished.

She stumbled, putting a hand on the rock wall beside her. She leaned her head on it, closing her eyes. Her heartbeat thumped against the inside of her skull.

"You compromised your own health by giving the cure to that boy," said Danse.

"He's just a kid," murmured Ella. "Christ." A wave of dizziness washed over her.

"You need to be more careful if this mission is going to succeed," he continued.

She turned her head to look at him, still leaning against the wall. Her eyes felt too hot. "I couldn't just - take it for myself," she said. "It would have entirely defeated the point of going in there in the first place. We'd just be back where we started. Worse, because then we'd definitely know there wasn't anything we could do to help."

"That doesn't mean you have to put yourself at risk," he said. "You're the priority here."

"They said it was worse because of his age. And probably his immune system, from growing up in the vault." Her words sounded dull and heavy in her own ears.

"Your immune system was calibrated for a set of diseases that were last relevant two hundred years ago," he said. "It's not any better. What if this - illness - gets worse?"

"It should not." The robot following them spoke up again. They both turned to look at it, hovering a short way behind them. Its round white chassis gleamed in the sun, and it's three optical sensors were in almost constant motion. "You will note the molerats did not die of the strain they were infected with," it said. "The virus was designed to be stable in adult life forms."

Ella frowned at the robot's feminine French accent, ludicrously out of place. "Life forms," she repeated under her breath.

Danse turned back to her. "You should come back to the Prydwen," he said. "Get Knight-Captain Cade to take a look at you."

She turned back to him. "It just feels like the flu," she said. "It's not - you know, it's not bad."

"Out here, any disadvantage could be the one that kills you." His dark eyes were stern; his brows heavy.

She sighed, looking away. "What about you?" she asked. "Are you feeling okay? Did you get bitten or anything?"

He shook his head. "I'm fine."

"Are you ingesting adequate nutrition?" asked Curie, startling Ella again. "I estimate you weigh just under 80% of your optimal body mass index."

"I can't eat the food out here, Curie," Ella complained, turning to face the robot. The motion sent a wave of dizziness through her, and she gripped hard onto her power armour. "It's disgusting. Not real food at all. A ridiculous French stereotype like you has to appreciate that, right?"

"You think I am a-" the robot hesitated. "A stereotype? Doctor Collins told me I was based on a woman he once knew."

"Really?" asked Ella. "You've got the standard Miss Nanny voice module. Though - clearly your programming is something that's not factory spec." Speaking was an effort. Her mouth was dry, her words beginning to slur. "We almost bought one before - before the baby was born, instead of the Mr Handy, but Nate made this filthy joke, and-" She was suddenly overcome with a memory so vivid it bordered on a hallucination; sitting on her couch, one leg pulled up under her, watching Nate was leaning his elbows on the kitchen bench, one eyebrow raised.

Then, suddenly, Ella was back, hand slipping off the rock wall, her knees buckling under her. Danse leaped forward to grab hold of her before she hit the ground, the huge metal hands of his power armour hands deft and gentle.

"Sorry," she said. "S-sorry. I thought I - was sitting down."

"We need to get you back to the Prydwen as soon as possible." His tone left no room for argument.

"Yeah," she said, closing her eyes as she leant against him. "Okay. That was - quite bad."

He half-carried her to the bench by the cooking station. She slumped down on the wooden seat, pressing the heels of her hands into her eyes to block out the light.

"I'm going to signal a vertibird," he said. "I'll be right back."

"I don't think I got anything that's going to help what you've got," said Cricket. "Unless you're after a more permanent solution to your troubles."

"Don't tempt me," Ella mumbled, looking up at her through splayed fingers. Cricket's red-lined eyes were dubious, and she took a half-step away as Ella met her gaze.

"You don't look real good, lady," Cricket said.

"No kidding," mumbled Ella.

Curie hovered at the edge of Ella's vision. "The effects should get less serious over time."

"This cure you had," Ella said, turning to look at Curie. "You said the - uh, components had all been used up?"

"Almost," Curie said. "The organic compounds have expired and are no longer guaranteed effective or even the correct concentration. Transpiration loss across two centuries is unavoidable even in the most well-controlled environment."

Ella closed her eyes for a moment. "What about if we found more supplies?" she asked weakly. "Could you make more?"

"That would be - difficult," the robot said. "The compounds used in our research are not common. I anticipate our chances of finding them in the Commonwealth at 0.02%."

"There are pretty advanced laboratories out here," Ella said. "And hospitals. Do you know much about Boston?"

"Do you know much about chemical synthesis?" The robot's tone was polite, but was so pointed Ella had to laugh incredulously.

"No," she said.

"Then I do not see how we will accomplish your goal."

The robot's tone set her teeth on edge, and the smile faded from her face. She sat up straighter. "Well, okay. This disease is spread through fluids, right?" she asked, sharply. "It's not exactly hygienic out here. If I go to a doctor to get patched up or my rads flushed, there's a risk that anyone the doctor treats after me gets the same thing. Or I get bitten by a mosquito. Or if - if I get bitten by another molerat and don't manage to kill it immediately, it gets infected, takes the disease back to its nest, infects the rest of its pack, has infected children, spreads across the Commonwealth - if this virus is so potent it can kill a child within days, it could wipe out a generation of children, and we could do nothing about it. This is a huge potential public health problem. I'm surprised your programming doesn't allow you to grasp the scope of the problem, to be frank."

The robot hovered in the air in front of her, silent.

"How fast do molerats reproduce?" she demanded. "What are their migration patterns? Do you think it's uncommon for a kid to get bitten by a molerat out here? Can the virus jump species to dogs, or bears, or anything else out here? Can ghouls get it? Do I have to be careful who has contact with my blood if I'm injured? Ignoring this is not an option." Ella wanted to grab the robot by its spindly little arms and shake it. "It's not just me," she said, balling her hands into fists. "I'm not the only one potentially affected by this."

Just as quickly as it had arrived, the incandescence of her rage faded, leaving her exhausted. She closed her eyes, dropping her head back into her hands.

"I understand the - magnitude of the situation you have outlined," said Curie, quietly. "Give me some time to work on some predictive models. I will - I will find a solution."

"Alright," she said. "Look, there's a little town just north of Concord. Do you know where that is? I can meet you there later. After we get back."

"Yes," said Curie. "I have map records of pre-war Boston among my reference materials."

She let out a long breath. "Okay," she said. "Great."

Ella looked up as she heard Danse's footsteps approach.

"The vertibird is on its way," he said. "Can you walk?"

"Yeah," she said. "I think so. I don't know about walking in the power armour, though."

"I'll get a recruit to pick it up," he said.

They made their way slowly to a clear space by the water's edge, and watched the vertibird fly towards them, low over the horizon.

"They sold us," she said, quietly.

Danse turned towards her. "Who - sold us?"

"No, I mean - me. All of us before the war. The government sold us." She stared out over the decaying city skyline. "And I trusted them."

She turned to Danse. "That sounds naive," she said. "I don't mean I trusted them to do the right thing for our veterans, or spend our tax dollars wisely, but I never thought they'd sell us to - to be experiments." The words caught in her throat.

"I can't understand a government that would do that to its citizens," said Danse.

"I can't either," she said, haltingly. "I don't understand why they did it. Who was collecting it. What were they going to do with all the results. What were we for?"

"The level of corruption is unimaginable," he said. He turned to look down at her. "For what it's worth - I'm sorry."

"I guess it doesn't matter now," she said, quietly.

They stood back, shielding their eyes from the dust the vertibird kicked up as it came in to land.

"Are you going to be all right on the ride back to the Prydwen?" he asked.

"I probably won't be so great on the fixed minigun," she said, with a weak smile. "Should be able to stay in a seat, though."

"Of course," said Danse, as they walked towards the vertibird. "After you."