Note: Contains some violence, character death, and spoilers for the entire first series. I recently started reading The Mists of Avalon and was inspired by the way in which a character manages to separate her soul from her body to deliver a message (I'm trying to describe this in the least spoilery way possible!) and I thought, Merlin should do that! Thank you to Sophinisba for the beta.

"What do you think it is?" Merlin asked, trying and failing to keep his voice at a whisper.

"We'll never know if you don't keep quiet," Arthur hissed, giving him an irritated look. "Honestly, Merlin. Anyone would think that you'd never gone hunting before."

Merlin shrugged and tried to look apologetic, but around them the knights shifted uneasily. Merlin knew that they were no more eager than he was to find themselves in the woods hunting a mysterious creature so soon after the incident with the questing beast. Arthur's full strength had not yet returned but he was impatient to prove to his father and his people – and to himself – that he was just as capable as he had been before his injury. So when reports came from the scouts of strange tracks found in the forest and in the lands surrounding the castle, Arthur had quickly volunteered to investigate.

But so far they had found nothing other than the unusual tracks, which were unlike any creature they had ever seen. They had been following the trail for hours, and more than once Merlin had wondered if they were going around in circles.

At last they seemed to be making some progress. The tracks led deeper into the forest before they unexpectedly branched off in two directions. Arthur signalled to his men, sending several of them to follow the tracks leading one way before he led Merlin and two other knights in the other direction.

"Keep close," Arthur said gruffly, but when he glanced at Merlin now he no longer seemed annoyed; his expression had softened to something far kinder and almost resembling a smile. "I don't want you wandering off and getting into trouble. As usual."

"That's funny," Merlin said. "I thought that you were the one always getting into trouble. Sire."

"That is because you have a severe mental affliction that obviously causes you to have delusions," Arthur said, truly smiling now.

"Oh, right," Merlin said, grinning. "I must have imagined it, then."

"Clearly," Arthur said. He bumped Merlin's shoulder with his own in a friendly way before forging ahead, his knights at his heels. "Now try and keep up for a change, Merlin. I'm busy enough hunting this beast; I don't want to have to track you down too."

Merlin opened his mouth to offer a retort, but no words ever came. He had no time to speak before he felt a sharp pain between his shoulder blades that sent him stumbling forward, followed by a crushing blow to the side of his head, and then the world went dark around him.

************************************************

When Merlin woke he found himself lying slumped against a broken wall, his wrists bound in manacles and attached to the wall by a heavy chain that seemed long enough to allow him to stand if he tried. He tested his bonds, trying to break them, but his magic was powerless against whatever sorcery had been used to enchant them. They would not budge.

Merlin tried to open his eyes but immediately winced at his first glimpse of the fading sunlight, which sent a searing pain through his skull and made his head throb fitfully. His face felt stiff on one side and he guessed that it was crusted with blood. The earth was damp beneath his knees and the air thrummed so heavily with ancient magic that Merlin knew he was at the Isle of the Blessed.

After a moment he gathered what little strength he had to open his eyes once more and look up into Nimueh's face.

She smiled at him, the curl of her lips cruel and familiar. "Hello, Merlin," she said. "It's good to see you again."

"You were dead," Merlin said, his voice sounding rough and harsh to his own ears, as if it had been years since he had spoken last.

"Did you really think that your magic was a match for mine?" Nimueh asked, sounding amused. She stepped closer to Merlin, towering over him as he crouched on the ground, lacking even the energy to stand. "You destroyed my body, yes, but that is easily replaced if one has the necessary power and skill."

"What have you done with Arthur?" Merlin demanded. "Is he here? Have you killed him?"

"Arthur is not destined to die at my hand," Nimueh replied. "He is safe, for now. You, however…" Wispy tendrils of flames formed at her fingertips, growing stronger and brighter as she thoughtfully considered Merlin for a long moment.

Merlin gazed back at her steadily, defiantly. He could feel an itch in his palms, his own magic awakening and wanting to fight, though it felt dimmer than usual. Although he thought he would be able to defend himself against Nimueh if she should attempt to strike him, Merlin didn't dare attack her first. Not when he was so weakened and she was at her full strength. As feeble as he felt right now, Merlin knew that he would never be able to call down the heavens as he had when he last fought her.

The flames shrank and disappeared, and Nimueh lowered her arm. "I asked you once before if you would join me," she said. "I'm asking you again now. What do you say, Merlin? Can we put the past aside and be friends?"

"Never," Merlin spat. "Your magic is cruel and selfish. I would rather die than join you."

"Do you not use your magic for your own ends?" Nimueh replied, her voice rising in anger. "You have used your gifts to kill others like yourself, and all for the prince you love. How is that not selfish?"

"One day Arthur will be the greatest king this land has ever seen," he said. "It is my destiny to protect him and defend him against any threat he faces."

"And who will protect you from him?" she asked, her face twisting into a sneer. "He is a Pendragon. He will turn against you the moment he discovers your secret."

"But I would still consider him a friend," Merlin said quietly. "My life is bound to Arthur's. Nothing you do will ever change that."

"How touching," Nimueh said. Her smile was sweet and bitter all at once. "I wonder what Arthur would say to that. Perhaps we should ask him when he arrives. He must be wondering where you are. I should tell him, and put his mind at ease."

Merlin's eyes narrowed. "Leave Arthur alone," he warned as he struggled to stand on unsteady legs, wanting to do something, anything to stop her.

"Or what?" Nimueh asked. She raised her hand and Merlin instantly felt a sharp pain sweep across his back and chest that seemed to squeeze all the air out of his lungs. It knocked him off his feet, sending him sprawling onto the ground panting for breath. "You are no match for me, warlock."

With great effort, Merlin forced himself to sit up, still breathing heavily. His arms felt like leaden weights, burdened by the chains, and his head throbbed more fiercely than ever. Nimueh watched him as Gaius sometimes looked at his experiments, as if Merlin were something she didn't quite understand.

Eventually Nimueh raised her arm again, and Merlin braced himself for another attack, testing the strength of his magic to see if he had recovered enough to defend himself. But Nimueh did not strike him; instead, as she moved her hand, a large oval shape appeared between them, like a mirror. Merlin flinched at the sight of his own reflection, pale and bruised and bloody, but beyond his image he could still see Nimueh as she stood behind the glass. Then the mirror rippled like lake water in a strong breeze, and the image transformed to show a familiar face: Morgana, asleep in her chambers.

"No," Merlin said desperately. "Leave her out of this." Morgana has enough trouble with dreams, he wanted to say, you'll make her go mad, but perhaps that was Nimueh's intent. She smiled as she waved her hand again, causing the image in the mirror to change rapidly, flickering from Morgana to the ruins on the Isle to Merlin looking so frail and hurt, and back again. Over and over the images changed until Morgana's sleep grew increasingly fitful.

"There," she said in satisfaction, lowering her arm and finally letting the mirror fade away. "Now Arthur will have news of you, and from a trusted source. I have no doubt that you will see your beloved prince soon."

"If you're trying to lay a trap for him, I will stop you," Merlin promised.

Nimueh laughed. "I don't need to set a trap for Arthur," she said, turning aside. "You are the only bait I need, Merlin." She gave him one last look before she strode away, disappearing behind a crumbled wall and leaving Merlin entirely alone.

Merlin watched her leave. He had to do something to warn Arthur, to keep him from walking into Nimueh's trap. Although she said that she would not kill Arthur outright, there was no telling what Nimueh had planned for him. She had left him for dead in the cave when he had gone searching for the morteus flower. Luring Arthur to the Isle of the Blessed might be part of an elaborate plot to destroy him and Camelot, or perhaps Nimueh just wanted to gloat over another prisoner.

Merlin knew that he had to stop Arthur from falling prey to her once again, but he had no idea how to prevent it. He tested the chains again but they still held firm. He was trapped; there was no way for him to escape from the Isle, at least not physically. He looked up and watched the birds circling overhead, small dark shapes against a grey sky, and suddenly remembered something he'd read in his spell book. He closed his eyes now, trying to recall the writing on the page.

The book formed in his mind and he mentally flipped through the pages until he found the one he wanted, the one that described how to separate one's spirit from one's body temporarily. It was old magic, dangerous magic, but Merlin thought he could do it. At least he had to try. Arthur's life depended on it.

Still picturing the book opened before him, Merlin said the words of the spell, concentrating all of his magic on finding Arthur. Nothing happened, and Merlin opened his eyes and glanced around in disappointment at the sight of the broken walls and standing stones surrounding him.

The book said that it might be easier to appear to a blood relation. Merlin bent all his magic towards Ealdor, picturing his mother and her small house, and said the spell again. He felt something shift deep inside him and suddenly he was flying, tumbling through the air formlessly as he was swept across the landscape until he found himself standing beside the fire in Hunith's house.

His mother sat at the table, wrapped in a shawl with her hair still neatly tied in its kerchief. It was late but she was still working, mending a dress, and Merlin wondered abruptly if he would ever see her again.

"Mother," he said, moving closer, but Hunith did not lift her head. She seemed unable to hear him speak.

"Mother," Merlin said again, standing beside her now, close enough to touch her arm. All at once Hunith shivered, tugging her shawl tighter around her shoulders as she glanced around, her eyes slipping over Merlin as she peered into the shadows. Then she smiled a little at herself, shaking her head, and returned to her sewing.

Merlin's shoulders drooped in disappointment. He had hoped that others would be able to see and hear him, but if his own mother could not, what chance did he have of warning Arthur? But Hunith had been able to sense that he was there, however slightly, and he thought that if he tried it again maybe, just maybe, his spirit would grow stronger and more visible.

Now that he had travelled once, Merlin was certain that he could do it again. Gaius was practically family; he thought of Merlin as his own son and seemed to be the next most sensible choice. Merlin pictured his little room in Gaius' chambers and found himself there in an instant.

"Gaius," he called, tripping down the steps. "Gaius!"

In the outer room Gaius was drowsing, but he suddenly startled into wakefulness. "Merlin?" he said, throwing his blanket aside and looking around. "Is that you?"

Like Hunith, Gaius was unable to see him but he had definitely heard his voice. He rushed past Merlin to climb the steps and peer hopefully into his room. Merlin felt just as disappointed as Gaius looked when he turned around and quietly shut the door to Merlin's room, his anxious face appearing older and more haggard than Merlin had ever seen.

But Merlin refused to give up now. He had already mastered movement and touch and voice. Now he just needed to do it once more, and make himself visible too, just long enough to warn Arthur.

He was already inside the castle. Merlin focused all of his magic on Arthur's chambers and in a moment he was there, standing before the table. Although it was late, Arthur was awake and putting on the last of his armour. He looked grim but determined, and Merlin knew that Morgana must have already told him about her dream.

"Arthur," he said quietly, moving closer so that he stood almost beside him. Arthur went very still and seemed to be listening carefully. Merlin dug deep, pulling together all of his magic and his power until he felt himself grow stronger, into something more solid and whole. "Arthur," he said again, louder this time.

In one fluid motion, Arthur drew his sword and turned to face him. "Merlin," he said, shocked, letting his sword drop slightly and Merlin felt a sudden burst of joy knowing that he could see and hear him. But then Arthur's expression turned angry and he lifted his weapon high once more. "What sorcery is this? Who are you?"

"Arthur, it's me," he said. "It's Merlin." He was desperate to make Arthur listen, to make him understand. His thoughts turned unbidden to the words he'd said when he had tried to say goodbye to him before leaving for the Isle of the Blessed to save his mother's life. You must learn to listen as well as you fight. Almost as quickly as the words formed in his mind they seemed to shift into Arthur's, and he dropped his sword onto the table with a clatter as he remembered their conversation.

"It really is you," he said wonderingly. "But Morgana dreamed of you tonight, she said you were wounded." Arthur suddenly grew pale. "Is that it, then? Are you dead?"

"No," Merlin said, though a small part of him wanted to say, Not yet. "I had to warn you. It's a trap. Don't come looking for me, no matter what Morgana dreams and no matter what Nimueh does."

Arthur's brow wrinkled in confusion. "Nimueh?"

"You remember, you met her in the cave when you were looking for the morteus flower," Merlin said. Arthur's eyes narrowed at the memory. "You mustn't listen to anything she tells you. She'll stop at nothing to destroy Camelot." He felt himself growing weak again, his power beginning to fail him. Merlin knew that he wouldn't be able to keep up the enchantment for much longer. "Look, just promise you won't do anything stupid. Arthur, are you listening to me?"

But Arthur did not answer. Watching Merlin closely, he reached out and rested his hand on his shoulder. Looking surprised that his hand did not pass straight through him, Arthur touched Merlin's face briefly before snatching his hand away as if burned. "You're so cold," he said. "How are you doing this?"

"It doesn't matter," Merlin said. He cast about for something to distract Arthur and return his attention to what was truly important, protecting himself and Camelot from Nimueh. And then he remembered the sword and the lake, and he knew what to do.

"Listen," he said. "There's a lake not far from here. At the bottom of it there's a sword, a sword that belongs to you." He envisioned the sword and the lake, creating a map in his mind and knowing that Arthur would see it too.

"To me?" Arthur repeated dubiously. "And what is the sword doing in a lake?"

"Well," Merlin said, feeling somewhat abashed. "I put it there, for safekeeping."

Arthur shook his head and smiled. "Now I know that you're really Merlin," he said. "No one else would do something so ridiculous."

Merlin smiled faintly. He felt his magic wavering, and used the last of his strength to keep himself there, with Arthur, so he could finish saying what he needed to say. "You must go to the lake and demand the sword's return. It will protect you against anything, even Nimueh, I think."

"But what about you?" Arthur said.

"I'll be fine," Merlin said. "Don't worry about me. Just – don't do anything stupid. Promise you won't try and find me." Arthur didn't answer. "Arthur, please – promise me."

But before he could respond Merlin's spirit flickered and fled, fading away from Arthur's chambers. It vanished from Camelot and hurtled towards the Isle of the Blessed, and Merlin felt something shifting inside him again as his spirit returned to his body once more.

He was still lying on the cold, damp ground, utterly exhausted and at the very end of his strength. Nimueh was nowhere in sight, and Merlin gratefully rested his head against the broken stone wall and let his eyes slip closed, knowing he had done all that he could to protect Arthur but still wishing he could have done more.

Merlin didn't know how long he slept. He woke several times but his mind was always muddled, and he had no sense of how much time had passed. Once when he opened his eyes he found Nimueh there, watching him coldly, and when she spoke Merlin could not understand what she said. His eyes closed again and he drifted back into unconsciousness.

And then, the next time Merlin woke, Arthur was there.

He was crouched beside Merlin, cradling his neck with one arm as his other hand lightly touched Merlin's limbs, assessing his injuries.

When Arthur felt Merlin stir he looked up, the relief evident in his eyes. "You're awake," he said, and helped Merlin to sit up.

Merlin smiled weakly. "I thought I told you not to follow me."

Arthur glared at him. "When have I ever listened to you?" He sat back and surveyed the chains on Merlin's wrists, testing their strength between his own gloved hands. "Let's get these off," he said, reaching for the sword at his side.

Merlin noticed the familiar golden blade that the dragon had burnished. "I thought you said you didn't listen to me."

"Don't worry," Arthur assured him. "I won't be making a habit of it. Hold still." He swung the sword and it hit the chain with a clang, but did nothing to slice through the links. Frowning, Arthur was about to try again but Merlin stopped him with a look. Nimueh was approaching them, moving soundlessly across the grass.

Arthur spun around, moving to stand protectively between Merlin and Nimueh. "Release him or I'll run you through."

Nimueh smiled, looking amused. "Your mortal weapon is no match for me," she said. She extended her arm and the sword suddenly burned white-hot. Arthur grimaced, undoubtedly feeling the scorching heat in his palm, but after a moment the glow faded and the sword returned to its normal colour.

"That's quite a blade you have," Nimueh said, sounding surprised. She turned to look at Merlin. "Was the enchantment your doing, warlock?"

"What?" Arthur said in disbelief. He turned to look at Merlin, his expression one of surprise and betrayal and hurt.

Merlin felt his heart sink. He had never wanted Arthur to find out like this. "I'm sorry," he said helplessly. "I meant to tell you."

Arthur looked away from Merlin, his expression unreadable now, and turned back to Nimueh. "I told you to release him," he said. "I won't ask you again."

"You really are two of a kind," Nimueh said, looking between Arthur and Merlin with undisguised glee. "So brave and so loyal. Or so it seems. Do you truly understand what you ask, Arthur? What would your father say if he knew you were assisting a dangerous sorcerer?"

Arthur said nothing, but continued to regard her steadily.

"Do you know the power that your servant wields?" Nimueh asked. "Do you know how many lives he has taken? He tried to take mine once. Do you worry that he will take yours?"

"I would never," Merlin snapped. "I would give my life for Arthur's."

"Yes, you did try that once," Nimueh agreed. At Arthur's questioning look she smiled again. "Merlin wanted to trade his life for yours when you lay dying. Would you have minded it, knowing now that he is a traitor to your kingdom?" She tilted her head, looking at Arthur curiously. "Would you mind it now?" she asked, and her arm suddenly reached out and sent a blast of light at Merlin, painfully flinging him against the wall.

"No!" Arthur said, anguished. He advanced on Nimueh but she knocked him off his feet easily with a sweep of her hand, his sword falling out of his reach as she kept him pinned him to the ground.

"Merlin, do something," Arthur ordered. Taking a deep breath, Merlin summoned all of his power and pushed back the light Nimueh was sending at him. He forced himself to his feet and raised his hand, speaking the same words as he had in the cave when he had faced the questing beast.

Merlin felt his eyes flashing gold as he used the last of his strength to lift the sword where it had fallen out of Arthur's grasp and send it flying straight into Nimueh's heart.

Nimueh looked at him for a moment, wide-eyed with shock, before she crumpled to the ground. The manacles on Merlin's wrists opened with a metallic clink and Arthur sat up, Nimueh's enchantments no longer restraining them. Arthur looked from her lifeless body to Merlin, stunned.

Merlin felt himself swaying on his feet, and he leaned against the wall unsteadily. "I'm sorry," he said again, before he felt himself falling and everything went dark.

************************************************

When Merlin woke again he knew at once that he was no longer on the Isle of the Blessed. The air did not hum with the old magic like it did on the island, and Merlin opened his eyes and craned his neck enough to see that he was lying on the shore. In the distance was the Isle, its ruined walls shrouded in mist.

Merlin let his head fall back against the grass and glanced aside to find Arthur sitting beside him, watching him closely.

"You're awake," he said, just as he had earlier. "I think you may even live. It's remarkable, really." Arthur was holding a wet cloth, half covered in blood and grime, and pressed it against Merlin's face once more, cleaning him. Merlin winced.

"Arthur, I-"

"Was she telling the truth?" Arthur asked. His expression was impossible for Merlin to decipher. "About the people you killed?"

"Yes," Merlin replied. "But I only ever did it as a last resort, when there was no other way to fix things. And I've only used magic to help you, Arthur. You have to believe me."

Arthur let the cloth fall away from Merlin's face and looked at him steadily. "I do believe you," he said at last. "You nearly told me once, didn't you? In Ealdor, before the battle."

"I can't believe you remember that."

"I do pay attention, even though I've been told that I should listen better," Arthur said, giving him a wry half-smile. "So your friend William-"

Merlin shook his head slightly. "He just said that to protect me," he said. "Will was no more a sorcerer than you are."

Arthur snorted at the thought. They fell quiet for a moment before Merlin asked, "How did you know where to find me?"

"I didn't. I had help from Gaius," Arthur confessed. "You mentioned Nimueh in that vision, and after what Morgana saw in her dream Gaius thought that I'd be able to find her here." He gave Merlin a sidelong look. "Do you think she's really dead?"

"I don't know," he said. "I thought I'd killed her the first time. But I didn't have your sword then. Maybe that made it work now."

"What did you use then?"

"I struck her with lightning," Merlin replied mildly. "She sort of exploded."

Arthur looked horrified and impressed all at once. He cleared his throat awkwardly and gestured to the sword, seemingly eager to change the subject. "Tell me more about this, then."

Merlin explained how it had been burnished by the dragon specifically for Arthur and that it was said to have great power. "But you mustn't let anyone else wield it," Merlin warned him. "Not even one of your most trusted knights. Not even your father. It's meant only for you."

Arthur drew the sword and looked at it, studying the writing on the golden blade for a long moment before he sheathed it. "I'll guard it as closely as I will your secret," he promised.

Merlin looked at him in surprise. "Really? You're not going to tell the king? Or banish me?" he asked uncertainly. "I thought you'd at least sack me after you found out."

"No, I'm going to keep you on," Arthur said. "A decent manservant is hard to come by, and you're quite good at cleaning my socks. Besides, some people might miss you."

"Will they?" Merlin asked, amused.

"Well, Gaius and Morgana and Gwen would, I suppose," Arthur said with a careless shrug. "And perhaps one or two others." He looked away then, turning to gaze across the water. "You won't always have to keep it a secret," he said quietly. "Until then, I'll do what I can to protect you."

Merlin smiled and touched Arthur's arm, waiting until he turned back to look at him before he spoke. "I know you'll be a great king someday," he said earnestly.

Arthur shrugged again, but seemed pleased by his words. "We'd better be on our way," he said, rising. "You don't have any broken bones; I checked. Do you think you can stand?"

With Arthur's help, Merlin was able to stand and mount his horse. Arthur swung up to sit behind him, and they rode back to Camelot.

When they finally approached the castle, a sentry spotted them and a number of people gathered in the courtyard to greet them. Uther pushed through the crowd just as Arthur helped Merlin down from the horse.

"Morgana told me that you had gone to battle a sorceress," Uther said, obviously displeased that Arthur had not told him personally. "Is she dead? And what did she want with the boy?" He gave Merlin a suspicious look.

"I apologise for not informing you, Father," Arthur said. "Nimueh captured my servant, thinking that he would provide her with information about me and Camelot. You can see by her treatment of him that Merlin would tell her nothing."

"Nimueh?" Uther visibly paled. "Where is she now?" he asked in a low, dangerous voice.

"She is dead," Arthur said. "By my own blade."

Uther took a deep breath and seemed to steady himself. "Good," he said, clapping Arthur's shoulder and looking at him with pride and obvious relief. "You showed today that sorcery is no match for Camelot's steel." He turned then to Merlin, and looked at him kindly. "Once again I am pleased by the loyalty you continue to show my son. Arthur, see that Gaius tends to the boy, and relieve him of his duties until he recovers his strength."

Arthur made a show of grumbling and complaining that he would have to find another manservant, but he brought Merlin to Gaius himself and waited in the physician's chambers, joined soon by Gwen and Morgana, until Gaius had tended to Merlin's injuries and assured them all that he would make a full recovery.

"I told you that you'd live," Arthur said much later, after Morgana and Gwen had gone and Merlin was settled in bed.

"Yes," Merlin said wryly. "Maybe you should give up on being king and become a physician instead."

Arthur rolled his eyes.

"Thank you," Merlin said. "For everything."

"See that you recover quickly," Arthur said abruptly, Merlin's gratitude apparently making him uncomfortable. "I have socks that need cleaning." He gave Merlin a considering look. "But you don't actually need to get out of bed to do your chores, do you? You could probably do everything from here." Arthur smiled, undoubtedly planning a long list of tasks for him to accomplish.

Merlin sat up and held out his hand, furrowing his brow in deep concentration. After a moment he fell back against his pillow as if he suddenly felt weary. "I hope it worked."

"What did you do?"

"I just cleaned your chambers," Merlin said. "At least, I hope I did. Sometimes accidents happen."

Arthur's eyes narrowed. "If you just exploded something in my room…"

Merlin smiled up at him innocently.

With an aggrieved look, Arthur turned and ran through the door. Grinning, Merlin watched him go and then closed his eyes, swiftly falling into a restful sleep.