A/N: This story won't have many chapters, but they will be long, so I decided to call them "parts" just because I could.

Part I: The Vulture's Attack

It was a fairly normal day for King Arthur, and he was enjoying a private breakfast with his wife and his best friend, marveling at how perfect everything was and thanking the Gods for it.

Suddenly, their peaceful meal was interrupted by the brusque entrance of sir Gwaine, one of the king's most loyal knights, who was panting as if he had run a mile on foot. "Blood, the water – it's turned into blood!" he managed to exclaim as he tried to regain his breath.

Arthur stood up, a worry line creasing his forehead as he reached the knight with quick strides, feeling the concerned eyes of both Guinevere and Merlin burning holes into his back. "Slow down, Gwaine. What happened?" he inquired, putting a comforting hand on the shorter man's shoulder.

"The water, princess," he began – Arthur had to fight the urge to roll his eyes at that ridiculous nickname. "The water from the pump has become red, just like blood. Everyone is panicking – they're not sure it's safe to drink and they won't last long without water," he continued, his eyes wide. Arthur was surprised by how shaken the man looked – it wasn't usual for Gwaine to be in such a state.

Arthur nodded and thanked the knight, dismissing him. He took Gwen's hand, promising he would make it up to her soon, and she playfully swatted it away. "Go," she said simply. He kissed her hurriedly while still managing to be gentle and tenderly caressed her swollen belly – their child would be born soon, and he couldn't help but smile at the thought, despite the tense situation.

He cast one last glance to his stunningly beautiful wife before turning around and gesturing for Merlin to follow him. The warlock obeyed silently, his brow furrowed in concentration, thinking about the possible causes of the strange phenomenon.

"Any ideas, Merlin?" the blonde asked, his eyes darting to the side for a moment.

The Court Sorcerer shook his head, biting his lip. "We should ask Gaius – he's the only one who knows what something like this could mean. I could turn the water back to its normal color, but I can't be sure that it will be completely safe. There might be a poison of some kind in it, and that's more of a Gaius thing," he explained, looking at his friend apologetically.

Arthur kept walking, waving a hand to dismiss the man's guilt. "It's fine, I know that I shouldn't expect too much from an idiot like you," he said fondly to alleviate the tension. He turned the corner to the right, Merlin hot on his heels. "Anyway, I'm sure you're right – Gaius surely knows what it is," he continued, gesturing with his hand to the nearest door, a faded 'Court Physician' still visible on the old wood.

They went in without knocking as usual, and were met by two narrowed grey eyes and a raised eyebrow. They gulped, knowing that when Gaius gave them 'the eyebrow of Doom' it meant that they had interrupted a difficult and potentially dangerous experiment. "What –" the old man began, but was interrupted by Merlin.

"We need your help, Gaius. The water from the pump has turned red, and I'm sure it's magic – I just don't know what kind of magic it is. A simple glamour, or a transformation spell? I need to know before I try to make it turn back as it was before," he explained quickly, his nervousness evident – he had been Court Sorcerer for less than two years, and he hated feeling useless.

Gaius nodded, his eyes steeling with determination, and picked up his tools before following the two men in the courtyard, where the water pump was.

When they arrived they were faced by a heartbreaking scene: men arguing, children crying and women attempting to soothe their young ones, while trying to hide their own tears of fear.

Arthur knew they had to do something – and quickly. The situation was grim and they needed to find a solution as soon as possible.

He was pulled out of his reverie by Merlin's hand on his shoulder. "It will be fine, Arthur," he whispered. "I'm sure it will. We've been through worse, haven't we?" he joked with a small smile as his eyes seemed to see through the blonde, slightly unfocused and wandering somewhere in the past – lost in one of the many memories he shared with his king.

Arthur nodded and looked at the former servant, willing his eyes to be able to express just how much he valued his council and, most of all, his friendship. "Yeah," he confirmed, and had to swallow the lump that had formed in his throat as he remembered how close he had been to lose Merlin.

He cringed as the memories came to him in a rush – his mind travelling back to two years in the past.

When Merlin had used magic in front of the whole court, Arthur had acted on instinct, ordering to the guards to seize him. The young man's betrayal had hurt so much – even more than Morgana's or Agravaine's – and he hadn't known why.

Maybe it was because the royal had always trusted the secret sorcerer implicitly – since that fateful day he had come to Camelot with an awed grin and bright eyes – and knowing that the boy had lied to him the whole time... He had never felt so stupid. So many things had changed since the day Arthur had met Merlin – Morgana had betrayed them, his father had died, he had married Guinevere and, finally, he had found out the reason behind Merlin's apparently strange personality.

He had been so angry, he remembered it clearly – the rage had burned in his heart like scorching flames, as the smoke they created obscured his view, clouding his judgment. He had wanted to kill Merlin, but Guinevere had convinced him to give the warlock a chance to explain. And when Merlin did, Arthur was hit by a torrent of emotions – guilt, gratitude, shame. The young man had lost so many things to make sure that Arthur was safe – learning about them had changed not only his opinion about his friend, but about magic as well.

From that moment on, every time Merlin performed a spell, even the mere conjuring of a flame, Arthur was always entranced by it, the same magic he had hated for so many years. And now he couldn't believe that he had once thought that magic was evil – not when he could only see beauty in it.

He shook his head. His mind had begun to stray too far from the matter at hand – it had been happening a lot lately, probably because of the most recent change in his life. The queen's pregnancy and the thought that he would be a father in a matter of weeks had made him realize just how much things had changed.

"Sire!" he heard someone shouting. Arthur almost jumped out of his skin as the voice shattered his thoughts. He turned – Gaius was calling him. Taking a deep breath, Arthur walked towards the old man. Merlin followed him, walking right beside him like he had always done – Arthur didn't miss the knowing look the warlock shot him. How the raven-haired man understood his every emotion was still a mystery to him, but he was unbelievably grateful for his constant support all the same.

They stared at the physician as he poured the red water into a vial and tapped at it, narrowing his eyes to see better. "Can you see here, sire?" he asked, pointing to where the liquid seemed to pulse. "The red color flickers if I shake the liquid, and that means this it is a simple glamour – the water is too pure to be completely tainted, so the magic disguising it is a bit unstable."

"So, Merlin," he said, turning his head to look at his former ward in the eye, "I'm sure you will be able to lift the spell easily," he said, patting the youth's back encouragingly. Arthur let out a breath he didn't know he had been holding and made to open his mouth to thank the old man, when Gaius stopped him by raising his hand.

"However, I think that we shouldn't underestimate whoever did this. This as a warning, sire. Red water means that blood is going to flow in rivers," he explained, his tone calm as usual, even if his eyes betrayed some kind of fear.

The king frowned. "A warning?" he repeated, furrowing his brow in concentration as he tried to understand.

"It means that someone is planning to attack Camelot," Merlin replied quietly. His fingers kept twisting the hem of his shirt, a habit he had recently developed to fight nervousness. "It means that someone has declared war against us. Right, Gaius?"

The physician nodded, raising the vial once again. "And I believe we all know who the attacker will be."

The royal nodded. "Morgana," he whispered, his tone hushed and bitter. He had finally stopped hoping that his sister would realize the error of her ways and come back to Camelot, that she would turn back into the fierce and compassionate lady he had grown up with.

"Can you make sure that the protective wards are active and working as they should, Merlin?" he requested tiredly, pinching the bridge of his nose with his fingers. The sorcerer nodded and scurried away, stopping to apologize hastily to the poor man he had tripped over, before racing off.

Arthur sighed and walked towards the castle, a sinking feeling in his gut telling him that the temporary peace they had lived in for the past couple of years had ended.

Months had passed since the water-turning-red event, and still nothing had happened.

Arthur had sent patrols every three days for weeks before giving up, but there had been no apparent sign of Morgana's supposed imminent attack.

He and Merlin had been on edge since the day Gaius had mentioned the witch's name. It had been a long couple of months for both of them, full of nervous fidgeting and anxiously looking over their shoulders.

Arthur was beginning to think that maybe they were just paranoid, and that the physician had been mistaken. Maybe some prankster had changed the color of the water for fun? It was still a possibility, after all, especially now that magic was legal. The king was almost completely sure that Morgana had nothing to do with it.

Things changed, though, when an unknown deadly illness began to spread through the lower town – although he didn't even know if it could be called an 'illness'. Men, women and children just dropped dead in the middle of doing something or passed away in their sleep, and there was no sign of wounds or sicknesses.

It scared Arthur more than he cared to admit to think that his subjects, the people he had sworn to protect with his life, could die so easily; one moment they were there, living and breathing and perfectly fine and then, they weren't – they were just... dead.

It was a deeply unsettling thought, one that filled his nights with horrible nightmares that made him wake up screaming – and he couldn't do anything at all to help Camelot.

At least that was what he had thought – until that moment, at least.

Merlin had come barging into his chambers, slamming the heavy wooden door against the wall and abruptly waking both the king and his wife.

After making sure that Gwen and the baby were fine and that being scared in such a way wouldn't harm them, Arthur dressed up quickly – he had finally learnt how to – and followed Merlin out. When they reached the throne room, the Court Sorcerer began to retaliate his and Gaius' latest findings.

"It's not an illness," he exclaimed quickly, his eyes wide with fear – it was such an unusual sight Arthur couldn't help but shiver as he saw his friend's terrified expression. "It's a curse. Someone used dark magic to make the people fall ill – someone has purposefully directed this sickness towards the lower town," he continued. "They know we will be weaker without the support of the people."

The king nodded, taken aback by the thought that there was something Merlin feared. "There's more, isn't there? I know you, Merlin, and I've learnt to know when you're saying the truth and when you're not. And I'm sure you haven't told me everything," he said calmly, but with a subtly menacing glint in his eyes. He and Merlin had a deal – no lies or half-truths between them – and the young sorcerer had apparently gone against his word.

Merlin gulped and nodded slowly, knowing that he would have to tell Arthur everything. "I – I can't remove the curse. Only a High Priestess of the Old Religion would be able to control such a complicate spell. It has already killed many innocents, and no matter how much I wish to, I can't help them," he explained, sighing defeatedly. "I'm sorry, Arthur," he whispered, suddenly finding his boots extremely interesting. "I'm so sorry."

The king interrupted his friend's self-pitying musings by putting his hand on the man's arm and squeezing it comfortingly. "I know, Merlin. I know you have already tried everything in your power. I guess we'll just have to wait and see how everything turns out," he said softly.

He turned away, with the intention of going back to sleep – it had been a tiring couple of days, and it was only the beginning – but Merlin's voice made him stop in his tracks.

"There is something else," he murmured quietly, shifting his weight from one foot to the other. Arthur had the chance to look at him properly for the first time in weeks. Merlin's eyes were bloodshot and almost glassy, and what little color he had in the face had vanished, while the bags under his eyes were as dark as bruises on his pale skin. He looked tired – no, he looked exhausted.

Arthur gave him his full attention. "What is it?" he inquired, his voice clearly showing his own tiredness.

Merlin seemed to hesitate for a moment, but after a taking deep breath he gave himself the strength to face the king and raised his head to meet the other man's eyes. "Mordred," he whispered, his voice nearly soundless. "I don't trust him."

The blonde frowned; Merlin had always been fond of the boy, maybe even more than himself. He had said to him, once, that Mordred would be the one to kill him – but after magic had been freed they had felt no need to fear the loyal young man. Merlin had even mentored him in learning magic, something he had never done before.

"What do you mean? Were you not the one who convinced me to train him as a knight? I thought you wanted him to symbolize that Camelot fully accepted magic," he said, utterly confused by his friend's words.

Merlin seemed conflicted, his brow furrowed in concentration. "I know, but... I fear it may have been a mistake," he declared, his expression guilty. "He was with me yesterday, when..." his voice broke and he bit his lip to fight the tears threatening to fall.

Arthur gave him the time he needed – Percival had, after all, being a close friend to both of them. Merlin, though, had shared a much stronger friendship with the gigantic knight than he had; they had been there for each other since Lancelot's tragic death and had discovered that they had a lot of things in common – like growing up without a father, spending their childhood in a village outside Camelot's borders, being able to cook (which made possible for them to spend more time together) and having lost many loved people in their lives. After Merlin's magic had been revealed, Percival had been the first – apart from Gaius and Gwaine – to stand up for him, since he was the only one of them who knew the goodness of magic, having lived with the Druids for a short period of time after his family's death.

That was why Percival's death had hit Merlin so hard – it was like losing Lancelot all over again. The knight had been one of the most recent victims of the strange illness, and – no matter how hard he had tried – Merlin hadn't been able to heal him. So, in addition to his grief, there was a deep guilt in his heart – he felt as though he had failed his friend.

Percival had been one of the few who lived in the castle – if not the only one – to fall ill, probably because he had tried to help in the lower town, where the curse was stronger. His kindness and big heart had led him to his grave.

Arthur knew everything, and so he gave Merlin the time to compose himself before continuing – the kindhearted knight had, after all, died only the day before, and his untimely passing was still an open wound.

The warlock took a shuddering breath, and swallowed the lump in his throat before continuing to speak. "Mordred was with me, yesterday, when I was talking to Percival, and I felt something in the air before Percival collapsed," he explained, his voice thick with unshed tears. "When I turned around... Before he put on the facade of the worried friend, I glimpsed a flash of a smile."

His next words made Arthur's eyes widen to the size of saucers.

"I fear he might be in league with Morgana," Merlin whispered, his tone pained. He didn't want to believe that Mordred, whom he saw as a younger brother, had taken part in such a monstrous plan – he didn't want to believe that he had indirectly killed so many innocent people, as well as Percival, who had been nothing but kind to the Druid.

The blonde swallowed, taking his friend's words in. If Merlin was right – as he often was – then they had a traitor in their midst. Mordred had been close to Morgana since she had hidden him in her chambers; who said he wasn't siding with her once again?

Arthur opened his mouth to speak, when suddenly the warning bell sounded. He met Merlin's blue eyes and saw fear there, the same fear that was mirrored into his own. He gulped and turned around, panicked, and his heart almost burst out of his chest when the door opened…

…To reveal a guard who had come to announce that they were under attack.

He breathed a sigh of relief, glad that it wasn't an attacker, but then he straightened, ready to face the real danger. He gave Merlin's shoulder a squeeze, knowing they didn't have time to speak, and nodded at him in a silent promise to continue later on.

As he ran toward the armory to get ready for the upcoming battle, little did he know that they would never have the chance to continue their conversation.

While Arthur and his knights were fighting, Merlin was scurrying trough his books to find a way to save the people who had fallen ill, safe in the knowledge that the king and his people were protected by his magical shields. Even if he couldn't remove the curse, there was still a chance that he would be able to save the sick and render the ones who were still healthy immune to the illness.

He was in the middle of reading the third book when the door of his chambers opened. He turned his head to scold whoever it was for not knocking, but the words died on his lips as he saw who was standing by the door.

"Mordred," he greeted, stiffening. He stood and walked towards the younger man, maintaining a safe distance. "Was there something you needed?" he asked, trying to keep his tone calm.

The boy had a strange expression on his face, an odd mix of amusement and pity. "Do you remember the Crystal of Neahtid, Merlin?" he inquired suddenly, his icy blue eyes turning to look at his mentor.

The warlock nodded, still confused. "Yes, I do. Why are you asking?"

The Druid's lips tightened for a moment and he just stood there, staring, before beginning to pace around Merlin – circling him as a vulture would, patiently waiting for its prey to be dead or defenseless before sinking its beak into the body's flesh.

Merlin was following Mordred's movements with his head, knowing that he couldn't lower his guard for a moment.

Mordred put his hand in his pocket and pulled out something covered by a piece of black cloth. He stepped closer to the other man, ignoring Merlin's tense stance, and removed the piece of fabric. "I found this," he said, showing his possession to the other man, "in the vaults. It comes from the Crystal Cave, just like the Crystal of Neahtid. I wanted to do some research on it with you," he explained, his smile strained and his eyes glinting maliciously.

The older man stepped forward, attracted by the Crystal just like a bee is by honey. He brushed it with his finger, not fearing its effects anymore – not now that he knew how to wield its power and its prophetic abilities. He took in its strange form, with one of the edges shaped to form a sharp point, just like the tip of a blade.

He raised his head questioningly and locked eyes with Mordred, feeling the Crystal calling to him. He tried to resist the urge to grab it from the knight's hands and throw it away. "Research?" he asked, his eyebrows shooting up in surprise. "What kind of research?"

Mordred smirked and pulled the Crystal towards him, before stabbing Merlin under the ribcage. His eyes were bright with joy as he took in the horrified and shocked expression of the most powerful sorcerer to ever live.

"I wanted to see if this precious jewel would be able to absorb your powers," he whispered in his ear, grinning devilishly. "It would seem that it's working well enough."

He twisted the dagger-shaped crystal in the warlock's gut and pulled it out with a squelching sound, smirking as Merlin fell on his knees before him. It was fitting, in his opinion; from that moment, after all, even the mighty Emrys would have to kneel before him.

The knight roughly picked the man up, disinterestedly noticing how light he was, and threw him over his shoulder.

He hummed softly while walking towards the dungeons, and he smiled when he felt the warmth of his former mentor's blood on his back, the red liquid permeating through the clothes. The steady drip-drop that rang softly whenever one of those crimson droplets fell to the ground was like music to his ears, an eerie melody that signed his first step towards triumph.

Merlin was shivering and gasping in his grasp, and Mordred felt almost dizzy with happiness when he heard the pain, both emotional and physical, in the magician's words. "Why?" the Court Sorcerer asked, his voice breaking – the Druid didn't know if Merlin was just blaming him or blaming himself for trusting him. Frankly, he didn't really care.

He felt, though, that the man deserved an answer – if only just to mock him for his stupidity. "Oh, don't you remember, Emrys?" he inquired innocently, spitting out the name as if it were an insult.

"I told you once that I would never forgive and that I would never forget. But don't you worry – it is nothing personal, we had to dispose of you because you were a danger to our plans," he explained, his tone macabrely cheerful.

It made Merlin nauseous to think about how foolish he had been when he had chosen to trust Mordred. He had known that the boy was dangerous – Kilgharrah had warned him plenty of times. Yet he had welcomed Mordred, and had even grown fond of him. His current condition was the punishment for his naivety.

A new wave of burning pain washed over him as Mordred's quick strides jousted his wound, leaving him gasping for breath. "What have you done to me?" he choked out.

The traitor smiled brightly – like a madman, Merlin thought – and patted the older man's shin with his hand, in a gesture of mock comfort. "The Crystal's magic is traveling in your body right now– it's in your own blood," he explained lightheartedly, as if they were merely discussing the weather.

"Those who can wield the crystals use them to see the future, feeding on their power to gain knowledge," he continued. "The Crystal is just taking what it deserves; it's feeding on your power, on your magic. It will eat away at your stored energy, using it as nourishment – every single moment you haven't lived yet, your potential energy. It will devour your future, tearing it to shreds, and when there is nothing left anymore... You will finally die," he concluded merrily with a joyful grin.

He halted suddenly, having arrived to the place he wanted; the dungeons. He opened a cell with his foot and unceremoniously flung Merlin in it. He locked the door with a golden flash of his eyes and walked away, singing in low tones a lullaby Morgana had taught him.

Merlin could hear Mordred's voice getting farther and farther away, until the only sound heard was of water dripping from the ceiling. Harsh gasps left his mouth, his chest heaving with the effort to breath and his face scrunched up in pain.

He whispered a spell to heal his wound, but it didn't work – the Crystal's magic was like poison in his veins, draining him of his powers – therefore tried to stem the blood flow by usual means, ripping a piece of his soaked shirt and bandaging it tightly around his chest and abdomen.

The events of the day finally caught up to him and he sat on the ground, resting his head on the wall. As he thought about the consequences of his imprisonment and the – hopefully temporary – loss of his powers he had to keep himself from panicking, knowing it would do nothing except from worsening his condition.

If Mordred was telling the truth... Then his shields wouldn't work for much longer, and Camelot would be unprotected against Morgana and the Saxons. Arthur would be unprotected.

The warlock shuddered in fear as a new and terrifying outcome dawned on him. Without Merlin by his side, keeping him from harm, protecting him with magic...

… Arthur would die.

TBC...