This one is very long. I didn't have time to pare it down, and I wanted to get it out before I forgot to.

Enjoy!

~Ra1n

Previously...

She walked in and was surprised to see that Gaius was standing a few feet away from the table, grasping the back of a chair with a white-knuckled grip. Merlin's left arm was dangling over the side, and all but that arm seemed to be clean. Before she could ask why, Gaius realized she was there. He turned his head to stare at her, rage flushing his cheeks as he ground out two words:

"Iron dust."

The words meant nothing to Gwen. Maybe she had heard him wrong? She set the bucket down on the table near Merlin's legs. Now that he was clean, Gaius had laid a sheet across his lower abdomen to protect at least a small amount of Merlin's privacy against anybody else who came into the room.

"Sorry?" she said.

"They...Arthur…" Gaius's rage seemed to be getting the better of him. "Iron dust. They used bloody iron dust…"

"Iron dust?" Gwen asked, dread pooling in her stomach. "What does it do?"

He attempted to keep a level tone. "Your father was a blacksmith. You can tell me what iron dust is."

Gwen thought back to her father, of his proud smile as he sharpened his swords, of the fine spray of sparks and sediment flying up and bouncing against his thick leather gloves.

"The iron that flecks off of blades? But how does that have anything to do with Merlin or Arthur?"

"Look at his arm, Guinevere," Gaius said, his voice taking on some urgency. He stood and began frantically flipping through books, searching for something. He seemed to find the page he wanted, because he jabbed his finger at it and shouted, "Quickly!"

Gwen rushed to lift Merlin's left arm, palm facing up. She had been wrong -his arm wasn't dirty. It was paper-white and felt just as fragile, and the "dirt" was an ugly, festering wound that started at his inner elbow and stretched halfway down his forearm.

"What do you see?" Gaius called, running his finger down the page, "Describe it to me!"

The skin was ragged around the edges, as if the wound was made with an uneven blade or with multiple sporadic slashes. It wasn't bleeding, but layers of skin were missing, and the exposed flesh underneath was mottled pink and red and black and yellow.

"It looks like a burn..." she said, looking away. Her stomach heaved. She didn't want to be studying Merlin's burn wounds.

Except-

She glanced back. Were burns always those colors? "...Only there's something not quite right about it."

"What? What doesn't look right about it?" He was still running his fingers along one of the pages of his books.

"I don't…" Gwen trailed off, unsure. It did look like a burn, at first glance. But as she looked at it longer, she became aware that the skin surrounding the wound wasn't untouched. Instead, veins were bulging right under the surface, snaking away from the damaged tissue and running up his arm before disappearing. They were a sickening green-grey through his thin skin.

"...it looks like... Blood poisoning?" Gwen bit her lip, "can you get blood poisoning from a burn?"

A few of Merlin's tendons twitched, his fingers curled, and a few more greyish tendrils threaded their way up and across Merlin's wrist.

"Gaius!" She shouted in alarm, not taking her eyes off of the spreading grey.

Gaius stood. "Let me see." Gwen turned the arm, but Gaius simply seized it from her grasp and squinted at it.

"His veins-" Gwen began, but Gaius shushed her, running his fingers along the corrupted vessels. He felt Merlin's forehead, then his arm, then his forehead again.

And then he pressed his finger right into the center of the gash.

Gwen squeaked in surprise and disgust, and Gaius hissed and pulled his hand back as if he, too, had been burned.

"Just as I feared," he said, turning and flipping through another book. "We're going to need more water!" he shouted over his shoulder, "And lots of it!" Rifling through his herb stores, he muttered, "Calendula… Calendula...Ah!" He held a small jar of dull orange blossoms in the air, and saw that Gwen was still standing in the room. "Go!"

Gwen didn't even ask. She just jumped and ran, grabbing a pair of buckets on her way out.

When she returned with her arms filled with the weight of the water, Gaius was frantically grinding the orange blossoms in a bowl.

"This should stop the infection," he muttered, "those bastards…"

"Infection? Is that what that is?"

She placed the buckets with the first one and stole a nervous glance towards Merlin. It didn't look like any infection Gwen had ever seen.

"Yes, and no," Gaius said, still crushing the blossoms.

"Then what is wrong with his arm?"

Instead of responding, Gaius lifted the bowl and began spooning honey and water into it. The blossoms crackled and turned a more vibrant hue of orange. He waited a few seconds as the paste thickened.

"I'm going to need you to hold his arm still. Whatever you do, you keep his arm still. Do you understand? It is important."

Gwen was becoming increasingly confused and frustrated. Gaius moved the buckets of water off of the table and placed them by his feet.

"Fine," she snapped. Merlin hadn't moved save for a few twitches and whimpers since she had come in. Gaius was giving her busywork. She braced her hands against Merlin's forearm.

"Now will you tell me what's happened?"

It seemed as if he hadn't even heard her.

"Are you ready, Guinevere?" Gaius was holding the bowl over Merlin's injured arm.

"Ready for what?" Gwen asked, exasperated.

In response, Gaius tipped a spoonful of the paste onto the burn.

Merlin's eyes shot open.

Gwen suddenly found her job difficult as the young warlock let out a cry and began thrashing violently. Gwen nearly let go, but compensated by leaning most of her weight into the limb, horrified. Gaius spread a little more paste over the wound, covering the gaping hole entirely. Merlin's thrashing intensified. The pale tendons in his neck stood out in sharp relief against the dark collar still cinched around his throat.

"Gaius-" Gwen gasped, but her voice was drowned out by Merlin as he opened his mouth and let out a hoarse yell.

Gaius frowned deeply, studying the wound as the mixture crackled along Merlin's torn skin. After what seemed like an eternity, Gaius thrust his hand into a bucket of water on the floor and lifted out a goblet-full, pouring the contents over his arm and washing away most of the orange substance.

Merlin stopped yelling, his thrashing slowing slightly as he gasped in lungfuls of air. Gwen relaxed.

And then Gaius spooned more of the paste over the wound.

Merlin's back arched off of the table as the mixture popped and hissed. He screamed again, but this time it was sharper, more desperate.

"P-Please!" he shrieked, words twisted into his screaming, "I p-pr-promise, I didn't d-do anything! I d-d-don't know a-anything, I swear!" Gaius poured another cup of water across the burn. Gwen had only a moment to register that it was coming away a duller color before it was replaced by another spoonful.

"Y-You lied!" Merlin sobbed, "You said you w-would stop. Y-You said you would stop! Please, please, I promise...!"

Gwen's grip began to slide as water-honeyed pulp flowed over her fingers. She leaned more weight into the arm.

"Gaius!" She yelled again as another cup of water brought forth a wave of greyish pus, "Gaius, what are you doing?!"

"Just...Just wait a little longer!" Gaius shouted, repeating the rinsing process. Merlin's movements were weakening, but he was still begging and jerking beneath Gwen's touch.

Gwen's eyes creased with worry, but she held on.

She didn't know how long it went on, but by the end, everybody was exhausted. Merlin's movements had slowed until he was just trembling, tremors moving up and down his body in sporadic bursts. The burn had started to bleed and was running in rivulets down both his and Gwen's arms.

Gaius rinsed his arm a final time. Merlin lay on the table with his eyes screwed shut.

"Y-you said it would stop," he whimpered, "A-And y-you said you w-would come b-back. Y-you p-promised. I-I did e-everything you asked, a-and y-you promised… y-you said...y-you s-said…"

Gwen released the arm, backing away. Merlin's fingers twitched, but he didn't seem to have enough strength to move any more. His eyelids fluttered, his gaze sluggishly moving towards hers. There was no recognition in his eyes as a final spasm rocked his body and he passed out.

Gwen immediately whirled on Gaius.

"What was that? What just happened? What did I just help you do?" She'd never heard screams like that, full of so much agony and despair, and she didn't want to think she had been the cause of them.

Gaius hesitated. "It is not important right now." He stooped to place the bowl on the floor next to the now-empty water buckets. He grunted as he straightened again, and Gwen was struck with how old he looked. He'd aged in the last month, as if the weight of the world was slowly pulling him towards the floor. "What are important are the injuries we don't know about yet. Please, help me sit him up."

She didn't move.

"Guinevere?"

She was staring at Merlin.

"Guinevere."

She jumped.

"Please. Help me sit him up."

She moved almost robotically, sliding her hand under his sharp spine and neck. Her fingers made contact with the cold collar as they eased the man into an upright position. Gwen held his shoulders to keep him from falling when he started to slouch forward. They were so narrow.

Like a child.

"Can… can we at least take the collar off?" She whispered, brushing one of her thumbs against it. "Please?"

Gaius looked pained. "I'm not sure we can right now."

Her voice didn't get any louder, but her breathing sped up. "But..."

"Guinevere, it does not matter right now. His physical injuries-"

"But what about later? Can we take it off later? He-"

"Please, you need to focus right now. The collar is the least of our worries. His breathing-"

"But- But it's not like he's stuck with that thing forever, is it? He can't wear a collar for the rest of his life! He-"

"Guinevere!" Gaius raised his voice. "You need to calm down. I have no intention of leaving the collar on."

"But you said-"

"Dammit, Guinevere! If we don't start helping him now, he might not have a 'rest of his life' at all! Now will you please focus and help me?!"

That got Gwen to shut up. Gaius took a breath. He didn't regret what he had just said, but he did regret the need to use such words.

"I'm sorry, but I need your help and I need you to understand the gravity of what is going on."

"Then tell me!" Gwen burst out, and Gaius was startled by the sudden change in tone. "I've been asking you what is going on for the last hour and you keep saying it isn't important, when obviously it is! If you want me to help, then you need to start including me! Where was Merlin? What does iron dust do? Why was he screaming those things? Where did all of this come from?"

She looked pointedly at Merlin's bared torso, lined with trauma. Gaius noticed that her hands, bracing Merlin's shoulders, were still stained with his blood.

"I know you are trying to protect me, but, please, stop! I don't know what they do to sorcerers, I can't even guess, but you obviously do and you can't keep hiding it from me!"

Gaius was stunned. For a moment, neither of them spoke. Gwen stood glaring at Gaius, her chest heaving.

Between them, Merlin remained bonelessly in Gwen's arms.

Gaius took a deep breath.

"His fever should start going down now."

Gwen continued to glare at him. "Gaius-"

He cut her off, his eyes a warning.

"Hush. Can you wrap his ribs? I believe he will have at least a few that are broken. I don't think I am strong enough to do it tightly, and I am afraid that he won't be able to breathe properly if his ribs aren't set soon..."

He lifted a roll of bandages and a small jar of honey from his table and held them out to Gwen. Gwen shifted her grip on Merlin and took them, but didn't move to use them.

"Tell me, Gaius." It was an order. It was obvious Gaius knew at least some of what had happened to Merlin, because he hadn't even checked his ribs yet.

Gaius sighed. He knew he needed to start speaking. Even if the methods for interrogating sorcerers had changed a little since the Purge, the basics were more than likely the same, and Gwen was right. She couldn't help if she didn't understand.

"Iron dust is not just a by-product of bladesmithing," Gaius nodded towards the bandages, urging her to begin with the more minor injuries. "It has many other uses. But most of them are utilized in potion-making."

He took some of Merlin's dead weight and began the slow process of running his fingers over each of his prominent ribs, seeking out breaks and cracks. Gwen straightened, her glare softening as she realized he was finally explaining things to her.

"But there are… other uses."

Gwen glanced at Merlin's bleeding arm. Gaius breathed deeply.

"Are you sure you want to know these things?"

She nodded.

"Very well," Gaius sighed. "During the Purge, it was discovered that iron, along with its many medical and practical properties, also served a very magical purpose as well."

Gwen undid one of the bandages and began wrapping it around his thin wrist. She covered the ligature marks, wishing that not being able to see them meant they weren't there.

"They found that if a sorcerer was bound by iron, he no longer had access to his magic. So Uther, naturally, decreed that all chains in the kingdom should be made of iron, and... he began to experiment." Pause. Breathe. There was a cracked rib on his left side. He brought it to Gwen's attention before continuing.

"There were… a lot of things that Uther did that I would not like to discuss. And things I would not like to think about. But one of the things he found was iron dust was extremely versatile. Better than straight iron. It could be hidden in a great many things, and mixed with things, to render sorcerers weak, sick, powerless, or physically incapable, amongst other things, depending on the dose and how it was administered." Pause. There was a broken rib, just above the cracked one. Gaius grimaced.

"And so he began to use the dust in the standard procedure of interrogating sorcerers...should I stop?"

Gwen looked slightly ill. Interrogation. Merlin had been interrogated. She'd already known, she supposed, but she didn't like to hear the words out loud.

"No," she said, a little too forcefully. She breathed, "No, I'll be fine, keep going."

Gaius gave her a concerned look, but carried on, "The quickest way to administer iron dust is through the digestive tract or through the bloodstream. Digestive tract causes more general weakness and sickness. The bloodstream, however, is far more painful and potent. It essentially contaminates a sorcerer's magic through their blood. If done correctly, iron dust can keep sorcerers subdued for prolonged lengths of time by trapping them in a kind of drugged limbo. In Merlin's case…"

Another broken rib. Gaius swallowed. "...In Merlin's case, I think they used a very crude method to get it into his bloodstream. In its essence, the procedure is supposed to be similar to a bloodletting. A vein is opened up, blood is drained, collected, mixed with iron dust, and poured or pumped back into the wound. The veins can be left open for days, with iron constantly circulating. It is supposed to be a very sterile, clean procedure. There used to be specialists…"

He could still remember the smell of the blood, the cries of sorcerers as their veins were invaded and abused. Gaius shook his head to clear it of the memories. "But the days of the Purge are over, and I suspect that Merlin's treatment was performed by nothing more than a few prison guards operating under vague verbal instructions." He pointed to the jagged edges of the wound. "You see the serration? It took them a few tries to open a vein, and they did not know how to keep it open once they got one. They just opened a different place each time, or reopened the scabs in order to administer additional dust."

Gwen was staring at him with her mouth open slightly. He sighed.

"I really think I should stop."

"No, I'm sorry. I need to know, I do."

He opened his mouth to protest, but Gwen was looking at him with wide, pleading eyes, so he closed it and grit his teeth.

"The effects are stronger the longer the dust is kept in his system. There is no way of knowing how long that has been, before you ask me."

Two more broken ribs.

"But it didn't spread that far," Gwen said. It was as if Gaius had read her mind, "I mean, I could see where the iron was, and it didn't even reach his shoulder, so it couldn't have been that long."

Gaius shook his head. "It doesn't work like that."

"What do you mean, it doesn't work like that?" She asked, "How does it work?"

"Like I said, they reopened the vein multiple times. There's no way of knowing how often the procedure was administered. The grey in his veins was just build-up from different sessions."

Gwen looked horrified.

"Then what did we…?"

"What we just did…" he motioned towards the table, still wet with watered-down pus and grey-orange petals, "was clean the wound, that is all. The calendula draws the built-up iron out of the surrounding tissue, and the honey staves off further infection, but Merlin is going to need to work the rest out of his system on his own."

"And how long will that take?"

"Everything depends on how much he was given." It was vicious loop of I-don't-know's.

"And we don't know that." Gwen said.

"No."

"And there's no way to figure that out."

"Exactly."

Gwen huffed. Gaius moved to check Merlin's other side.

"You wanted me to be honest?"

Gwen nodded. "Yes."

Gaius took another breath. He might as well put everything out on the table.

"His fever…" he started, "is abnormal for the procedure, and that is not the only thing I am worried about."

Gwen mentally prepared herself as Gaius began to explain.