He was folding one of Arthur's shirts, feeling the clean, crisp material twist willingly under his practised fingers, when he realised that Gaius was talking to him. He couldn't really hear what he was saying; the window was open and the room was filled with the sound of cheerful birds. Not that it mattered. Gaius would tell him about whatever it was later as they sat together having their evening soup.

"Please," he said, warding off any argument or statement that he wasn't paying attention or taking his guardian seriously, or saving Camelot at that particular moment. After all, some things could wait. "I need to get this finished."

"It is important, Merlin."

"More important than Arthur's shirts? You know how he gets."

"So does that mean you're not going to do it?"

He glanced up, his fingers working on the sleeves to get the creases just right. Arthur hated creases in the wrong places, like he hated under-shined buttons and the nap running in all different directions on his velvet coat. Merlin grinned at the dark-haired knight. "As I said to Gaius, Lancelot, I need to get this finished first."

"Need to get what finished?" Arthur looked to be in a hurry as he strode in, removing bits of armour and dropping them to the floor as he breezed past.

Lancelot came closer and smiled broadly, squeezing his arm. "Don't let him get to you," he said, and turned to go.

Merlin didn't watch him as he walked out, his eyes on Arthur. "Your laundry sire. You always get grumpy if you don't have clean shirts."

"Yes yes, but I always do, Merlin. You make sure of that. Help me with this." He tugged at him mail shirt, and Merlin immediately crossed towards him and pulled it off. It felt so light in his hands, like it was made of nothing, and he clutched it to his chest, feeling how soft it was. Amazing that it gave so much protection on the battlefield.

"Now I want you to do something for me Merlin."

He looked over at his King. "Anything sire, you know that."

Arthur smiled broadly, and reached out to clap him on the back. "Come with me then," he said, crossing to a grand door in the wall of his chambers.

Merlin looked down. The mail shirt in his arms had disappeared. Oh. Convenient. He forgot about it and walked over to stand beside Arthur.

The door in front of them was small, but iron clad, and covered in bolts and locks. Arthur leaned over and opened it with a tug. Inside was as black as a wolf's throat.

"I need it cleaned," the King said, running his finger around the inside of the doorframe, and bringing it back black. "I don't think anyone's been down there for years," he confided in a whisper.

"But it's dark," Merlin said, moving back slightly. "I'll need a light."

"Don't be ridiculous Merlin, who needs a light to clean with?" He took a firm hold of his servant's arm. "Now in you get. Don't be such a wet petticoat."

"Arthur no!"

"Merlin it's just a cupboard. Stop making such a fuss!"

"Please, don't, please…!"

"In you get," Arthur shoved him forward, and he felt his hands collide sharply with the stone wall opposite the door, scuffing the skin, and sending pain slamming through his wrists. He turned, but the door was already shut.

"Arthur don't!" He ran forward and scratched at the door desperately, like an animal stuck in a trap and tearing at the ground in terror. His nails snapped under the onslaught, and he brought his hands back to his chest protectively.

All around him was inky blackness and he had the sudden, overwhelming sense that wherever he was, he'd been there before, and he was trapped now, trapped with no way out. Arthur had engineered this, Arthur had wanted him here.

"But you said you only wanted me to clean!" he wailed to the darkness, knowing full well that no one could hear him.

Then a face loomed from the darkness, a stranger with dark hair and torn clothes and sorrowful eyes. "You'll be here forever you know," the voice said. "If I don't eat your flesh before it rots."

As the stranger's ugly long fingers reached out for him, Merlin started violently, clutching at the sheets around him with a tight spasm of his hands and slowly becoming conscious and aware as the dream faded and the bed beneath his body solidified.

His breath hitched, and he blinked his eyes, pressed down into his mattress by the heavy weight of fear that had followed him back to a wakeful state.

"Are you alright?"

The voice prompted him to move, as he breathed in shock, turning his head and blinking again, instantly screwing up his eyes at the flash of hateful sunlight. There was a creak and the light dimmed suddenly.

"Sorry," the voice he knew was Arthur, and the King he guessed had been standing with the door to his room wide open, allowing the bright light to stream through. A blanket still hung over his own window to keep the worst of it out, though Gaius told him daily now that he should remove it; that his eyes would never adjust if he didn't give them the chance.

"What do you want?" he asked in a low voice, trying to force his eyes open again.

"I heard noises," Arthur said. "Gaius wasn't here. I just came to see if you were okay."

"Fine," Merlin responded, not looking in his direction and still touched by the darkness of his dream.

There was a brief silence. It lasted an eternity.

"Can we talk?"

Merlin struggled with his dry throat, reaching out for the cup of water on his bedside table and sitting up to drink it.

He took a gulp, it felt like he'd swallowed a stone. "We have nothing to say to each other."

"I would disagree with that."

The King finally came into focus and he watched him over the top of his cup before putting it back down. "Say what you have to say," he muttered. "Then leave."

His tone brought Arthur's chin up, and he had the impression that the King wanted to rebuke him, but stayed his tongue. He continued watching him darkly.

"I want to fix this."

"Fix what?"

"Us."

"What's to fix?"

Arthur looked surprised at that, but he said: "I did a terrible thing to you, Merlin, an awful, terrible thing, and I'm sorry. I want to make it up to you."

Blink.

"Is that it?"

Arthur gaped. "Is that it? I'm standing here apologising to you!"

"And you want me to be… grateful for that?"

"I want you to at least acknowledge it!"

"Why, so that you can feel better?"

"So that we can move on."

"Ah, I see. You want to put this whole unfortunate episode behind us. Well, that's a little easier for you than it is for me."

Arthur looked at him, seeing him in his crumpled sleeping clothes, his hair hanging long over his eyes, his black beard. He barely recognised his friend.

"I'm sorry Merlin," he said in a different tone, shaking his head. "I truly am sorry. Gaius told me, told me everything that you've done for me over the long years you've been here. He told me about breaking enchantments, about protecting me from Morgana. How it was you and not me who defeated the dragon, who saved me from assassins and even made sure that I ended up with the one I love. I know now the sacrifices you've made for me, and I know that nothing I could ever say would make up for all of that. And for what I did. But you must let me try. Please. Let me fix this."

Merlin looked down. "Okay," he said. "Give me back the light."

Arthur looked confused. "What?"

"The light," he said, a little louder. "And my pride and dignity. You took those from me, Arthur, didn't you know? And you gave me nothing back but a fear of the dark. But do you know what you really took from me?" He looked up. "What locking me in a stinking hole without the sun and without my family, and without even one chance to tell you my side of the story? You know what that destroyed? My faith in you. My love for you as a King.

"All my years here, I've done it all for you, everything, I would have died for you. And when you had the chance to prove yourself to me, to prove that you could be a truly just and worthy King, you fell upon a stony shore." Merlin shook his head, tears starting in his eyes, his voice becoming emotional. "I'd always hoped for a better future, I'd always seen you there, as this shining figure of light, this great... King, the greatest King that Camelot had ever seen. And it's gone now! You took that from me. You took the purpose of everything I worked for." He shook his head. "You can't fix this Arthur."

Arthur swallowed, moved to silence.

Merlin shook his head, tears dripping down onto the blankets crumpled in his lap. "Please," he said. "Leave me be. I can't be a part of all this any more. You need to rule and be your own King, whatever King you're going to be and just let me go."

Arthur stepped forward. "Merlin, I can't do this without you."

"You should have thought of that before!" Merlin yelled, fury rising and giving him strength as he pushed himself forwards on the bed, kneeling up, fists clenched. "I will not forgive you! I will never forgive you! And I will not help you! You are nothing to me now, Arthur, but the shadow of a friend I once knew. Just get out, before I do something I'll regret!"

Arthur staggered backwards a small step, his eyes going wide, his hand slipping unconsciously to his sword at the waves of anger rolling towards him.

Hard-won friendships have foundations of stone. They build like stalagmites, slowly compounding themselves over days and weeks of words and encounters and tiny gestures, and trust and laughter and tears. But all rock can be shattered when ice creeps through its weaknesses and flaws, expanding and forcing the cracks open into gaping wounds. And of course, once broken it will never be the same. A friendship is never the same. A darkness paws at the shadows.

He was a fool to think he could walk in here and they could be as they always had been.

"What's going on in here?"

The voice drew his gaze away from Merlin, and he saw Gaius standing at the open door, one hand on the frame. He took another step into the room, concern evident on his face.

Arthur glanced back at Merlin, and then to the physician.

"Forgive me," he said, and left hurriedly, never once looking back.

"I've destroyed everything," he said. "Everything. I've let anger and hatred blind me, and I've ruined a life, a life I should have been celebrating."

He almost flinched at the feel of her hand on his neck. He'd missed her touch. She sidled onto the bed beside him.

"I can't believe I did it, Gwen. I can't believe I did it to him."

"You can't change the past Arthur," she slid her hand into his. "But this is Merlin we're talking about. He will forgive you. You just need to give it more time."

"It's not him any more," he said shaking his head. "If you could have seen him. I've killed everything he was. It would have been kinder if I'd just…"

"I did see him," she corrected quickly. "He wasn't himself. He's sick, he's still…"

"I did that to him, Gwen. I made him sick; I've changed him. And I can't make it right. There's nothing I can do. He's right, I should just let him go."

"You've tried your best."

He laughed without humour. "This time my best wasn't good enough. Out-ranked by my worst, I fear."

"Then make him see sense."

"How?" he asked, incredulous. "He has every right to feel the way he does. If someone had done that to me… it was so unjust! I didn't even give him a trial. I didn't listen to anything anyone said. I just went on instinct, and it was so wrong."

She wrapped her arm around him tentatively, their make up still fresh and hesitant. She'd moved back into his chambers, though often she would still slip away before night fell.

"Arthur you are the bravest man I know, but you give up too easily when it's not a foe to slay or a dragon to quell. These things between people are the hardest things to conquer. But they are also the most important. You have to do something to bring Merlin back to us. To prove how much he means to you, to Camelot. To prove how sorry you are."

"What?" he demanded.

"A gesture."

"What sort of gesture?"

"I don't know," she said. "Something you've never done before. Something he wouldn't expect."

"It's going to have to be pretty amazing," he retorted with a raw smile. "With Merlin I've always learnt to expect the unexpected."

She smiled back. "Then make it amazing." She stroked his cheek. "I do love you," she said. "You know that."

He turned his head and put a hand up to cover hers. "I don't deserve it."

"Well, I didn't say you deserved it," she said, her smile deepening as she leaned in to kiss him fondly. He relaxed into it, feeling his world get just a little bit brighter.

Then she leaned back. "Better?"

"I'm always better with you Guinevere. You make me better."

They held each other in silence. Arthur broke it.

"You know the one thing," he said. "When I was talking to Merlin, he was mad at me, crazy mad, so angry. And if what Gauis said is true, he's powerful enough to kill me with a thought. But he didn't so much as… he didn't use his magic on me, not even a little."

"Of course not," she looked confused. "He wouldn't."

Arthur looked up, his eyes falling on his sword across the room, the sacred sword that Merlin had persuaded him to pull out of solid stone. It glinted in the candlelight, its runes stark in the metal. He was still King, whatever he'd done, the reminders were all around him, reminders of the Kingdom he'd built with Merlin's help.

"I just – I don't know what to do."