A/N: Begins mid-episode 5.12 "The Diamond of the Day."

The Bravest Man

"Then it is at Camlann that we make our stand."

And exhaustion turned to despair, and fear to dread. Merlin felt sick to his stomach to hear that word, and the resolve in the king's tone.

When he was less than nothing. Weak, distracted, a failure.

He'd done nothing but delay the inevitable, when he'd been told – when he knew – he possessed the sheer power to affect change.

At least, he used to.

Merlin inhaled, and squared his shoulders, and after the council meeting was concluded, went to talk to Gaius in the physician's chambers with a calm exterior. He was no longer a boy to panic at the possibility – probability – of the king's death. It had seemed imminent before, after all, in spite of the prophecy.

No, he couldn't talk Arthur out of his plan of facing Morgana and her army at the mountain pass, remote from the city and its people. He'd only succeeded in talking Arthur out of anything a scant handful of times – and lately it seemed that the king had relied more and more on his own decision than the advice of his manservant.

As it should be, probably.

It wasn't hard to conclude that his own stand would have to be what it had always been – to protect Arthur as best he could. And that, with magic. Which thought led him to the Cave, and the dangerous Valley where it lay – and the knight who'd once before accompanied Merlin into Perilous lands for Arthur's sake.

Except… except.

He wasn't sure of anything, anymore. Maybe that was an effect of the loss of his magic. The loss of confidence in any ability he might have, to face this last challenge and actually prevail.

Maybe he'd die, killed at last by some filthy nameless bandit, and Gwaine with him, and no one would ever know what became of them. Labelled deserters, with all the shame that could bring on a man's name and memory. Maybe it wouldn't work, and he'd reach Camlann late and feeble – because of course he'd still go – but then, at least he could die fighting at Arthur's side.

"If I can't prevent him from going then I must protect him as best as I can…"

Which at the moment, still meant he looked after Arthur's armor. And nearly ten years' experience had made his skill in this part of his job, as valid as his physician's skills in tending the wounded from the garrison battle.

He spread the array on the table in Arthur's chamber carefully – every bit shined and repaired and strengthened. By hand alone, because what other choice did he have, all night in the armory. Because how was he supposed to sleep. And because he didn't know how else to say what he felt.

"I think you'll find that's everything, sire," he said, standing respectfully still and clutching his hands behind him. Because this time, he wasn't just going to disappear and leave Gaius to say, the tavern.

Arthur seemed to hear the pretense, anyway. He was suspicious of Merlin's motives, he was confused by Merlin's attempt to make a good excuse. Physician's assistant duties, made urgent by the upcoming battle and anticipation of injuries. I was running an errand for Gaius.

But he didn't believe Merlin. Disappointment was clear in his face, even as he said, "No, no, it's fine. It's fine. I understand."

But he didn't. Merlin knew what he thought, what he assumed, that he'd lost faith in his king's ability to win the battle, that he would keep his distance from the fighting to protect his own life because all the rest were lost, anyway.

It hurt, even more so because Merlin was afraid to his bones that part was true, that there was no way Arthur could survive Camlann, even if his magic returned, it would still be too late.

"I always thought you were the bravest man I ever met," Arthur said.

Merlin began to relax – maybe he did understand, after all. Some things were more important than a manservant traveling with the army's columns. But then Arthur voiced his disappointment and misunderstanding, with the sarcasm that was both shield for his own heart, and sword aimed at Merlin's.

"Guess I was wrong."

And maybe it was true, after all, that Merlin was not brave. That he was the coward Arthur assumed, as he turned his back on Merlin with excruciating indifference, feigned or not.

Guess I was wrong. Guess I was wrong… And maybe this was the last time he'd see Arthur. Alive, upright, breathing, unbloodied… and still totally blind to who Merlin really was, complicated and mistaken and broken and lonely.

He was too tired. Drawn too tight for too long with no support and no surcease.

Merlin snapped.

So much frustration. Not only with Arthur, but that's what came out, as his friend turned away. Snatching at the first piece of armor that came to hand – a heavy leather gauntlet – he hurled it at the back of Arthur's head as hard as he could.

The king flinched as the leather glove struck him on the back of the neck, between his shoulder blades. As it flopped to the floor, Arthur whirled with an expression of startled and incredulous outrage that almost made Merlin laugh out loud.

Hysteria. Nerves. An iron control to rival Arthur's best, slipping at last to release an overwhelming dissatisfaction with and disgust at himself.

"After all these years," Merlin said, trying to keep his tone level – and only partially succeeding. "After all the danger we faced together. If you think our ways part now because I'm afraid, then you did mean all those jokes!"

"Vital supplies," Arthur repeated, mocking sarcasm that stung like salt in a wound.

Once too often. And this time, Merlin couldn't swallow the forbidden word that he longed and feared to say.

"Magic."

Arthur went still.

And Merlin spat again, "Magic, sire. Or do you honestly think you have a chance of defeating Morgana without it, not to mention her army of Saxons? Marching to certain death is very noble of course – but it means nothing if it's not effective."

"What are you saying." Arthur's tone was dangerously even; his whole body alert. The rolled map forgotten in his hand at his side.

Me, Arthur. Me. Maybe I'm as brave as the knights or maybe I'm the biggest coward in the kingdom after all.

But he was tired of hiding, and it seemed like everything was ending, anyway.

"I've had magic all my life," he said. "I've used it for you and for Camelot, ever since we met." His voice trembled, and he didn't quite know the reason why – but then he had to correct himself. Must be truthful, in spite of the host of his lies. "I had magic, I mean. It's gone now, and I'm going with Gwaine to see if I can get it back so when I come to Camlann –"

Because I wouldn't leave you to face this alone, and it hurts to know you'd believe that of me –

"I will actually be of some use to you beyond staying up all night to polish every damn bit of armor you own!" His throat felt raw, and every breath was coming too fast; every breath scraped like even the air had edges, and it was making his eyes tear up.

Arthur took one step toward him, then two. And continued in the same slow pace til he reached the table – never taking his eyes from Merlin – and set the map-scroll down on the metal and leather Merlin had laid out so carefully and neatly. And with his hand so close to any number of bladed weapons, Merlin couldn't help an involuntary step back.

"What do you mean, it's gone now?" the king demanded.

Merlin blinked.

Arthur repeated himself. "What do you mean. It's gone now? Merlin?"

"You…" He found his voice with an effort, and it hurt his throat to speak, too. "You believe me. You didn't – you're not making fun, telling me I'm too much of an idiot, there's no way I have magic, because you'd… because you'd…"

"Because I'd know?" Arthur said.

Way too calmly. Merlin couldn't think what that meant, yet – something so deeply significant he hadn't reached the bottom of it; the sensation of falling continued.

"I did know," Arthur said. "Right now I'm more concerned about your explanation for it's gone, so –"

I did know. Ye gods…

"How long?" Merlin whispered. "You knew. Since when?"

Arthur exhaled. "This is not a good time for this," he remarked. He eyed Merlin, then gave a small shrug. "For a while, I guess. Nearly a year."

Merlin's whole world reeled.

At Ismere, when they'd been caught by the slavers and he couldn't use magic to free them from the net because Arthur was too close. And instead Mordred had saved Arthur's life – and returned to Camelot to the acclaim and honor and trust of knighthood.

At the stones of Nemeton, and later when Uther's spirit had discovered his magic…

At the grove of Breneved, when Merlin had committed heresy, and still failed to protect his king.

At the dark tower, and if he'd known that Arthur knew, he could have saved Elyan…

At the Cauldron. And did Arthur realize the actual identity of the Dolma, and was he laughing the whole time as Merlin made himself sick worrying about Gwen's reclamation and Mordred's presence – and then Aithusa and Morgana as well?

"How did you –" he said stiffly. "How did you –"

"Find out?" Arthur finished. "It wasn't like that. It was more of a… slow realization. Suspicions, discarded. Reawakened, rejected, repeated. I knew it, long before I admitted that was the only explanation for – so many things."

"So you've seen –" Merlin felt incapable of forming complete sentences. Glad that Arthur understood so easily – irritated that Arthur understood so easily.

"Nothing," Arthur said quickly, as if to correct a misconception. "Nothing definite. I tried not to, because that would mean…"

Yeah. Repercussions. Arrest-trial-execution kinds of repercussions.

"But you knew," Merlin repeated. "Almost a year."

Arthur nodded, and there was no fear or anger in his face, no sense of betrayal, only acceptance. Merlin had dreaded this moment for so long, convinced his punishment would include the end of any kind of relationship, the destruction of trust. Convinced it was going to be impossible for things to stay the same, so much so that he'd determined to keep lying and hiding for the rest of his life, for the sake of Arthur's survival and remaining servant to his master. He'd choked his own hope, squeezing his own heart ruthlessly into submission, denying his desires and –

For nothing. Unnecessary, for almost a year. The fear and pain and frustration…

He felt like the idiot Arthur was always calling him – for good reason, it seemed, though he'd always argued back in his own mind, mocking his prince and king for not seeing he wasn't an idiot.

He felt blind and stupid, like a child hiding in plain sight while Arthur was the adult who fondly indulged the illusion. Humiliation made him dizzily nauseated, for a moment. Guilt because this was exactly how he'd expected Arthur to feel, if and when he finally found out – and now their positions were reversed and he was angry. But still guilty.

"Every lie you heard me tell," he said.

And the one that hurt more than all the rest put together, the one that haunted his dreams – there can be no place in Camelot for magic. It still burned in his heart – hotter now than ever because there had been no point to it. No good to come of it in the end; Mordred lived and betrayed and hated and because of that, Morgana had known to send the gean canach…

Arthur rolled his eyes. "I didn't believe the things you told me because they made sense," he said. "I believed you. What I heard you say was, I'll take care of it no matter what, or Don't worry it's been handled."

Merlin should have been touched by that. Flattered, maybe – mollified, at least. But he only felt guilt-humiliation-fury, for the aching contortions of his conscience. The acceptance, rather than challenge, of mocking comments. Every sacrifice of his spirit he'd made this year. All for nothing.

He took a step toward his king, fists clenched at his side.

"You let me lie," he said.

Once again, Arthur stilled to seriousness. Not as if he'd suddenly been reminded that he could respect and even fear Merlin – he could force Arthur to that, he knew, and the thought, the fact that he'd think such a thought, made him sick. No, the sobering expression on the king's face was one Merlin knew for a sudden re-evaluation, maybe things weren't quite the way Arthur believed.

As if it hadn't occurred to him that Merlin could be anything but grateful to find out that his secret had been secretly discovered.

"You let me lie," he repeated to Arthur. "When every time it twisted me inside. When it was one more thing between us, pushing me away when I was trying to hang on, hiding who I truly was because I was sure you'd turn away if you ever really saw me. And tangling myself in knots –" he advanced another step, drawing his clenched fists up by his chest; Arthur dropped back a step – "trying to figure everything out on my own. And not make too many fatal mistakes and decide what was the lesser of two evils, and–"

He had to stop to breathe, but it didn't seem to help.

"You let me lie," he roared, and tears dripped down his face. Arthur flinched. "When it changed me."

"Merlin," Arthur said, in quiet shock. But not for Merlin's rare display of temper. "I didn't realize – I didn't want you to change. I didn't know you… felt this way."

"Ha!" he scoffed aloud, because scorn would provoke Arthur's arrogance. And he needed the king angry at him – it was what he deserved, it justified his fear of transparency and truth, it would lessen the guilt he felt for lies and secrets and this outburst. "Something you didn't know. There was a lot you didn't know, Arthur. Things I've done, with and without magic. So much I never told you, and you didn't notice."

"When you trust someone, you don't have to know all their secrets," Arthur said.

Merlin shuddered, the emotion was so raw.

Everything he wanted, everything he was afraid to want, because it seemed so impossible. Arthur knowing, meeting his eyes as an equal, confident. Nothing changed. Everything changed.

"What about the law?" he dared.

Outside the room, preparations for marching the army to war continued. They did not have much time, but some things were more important than time.

"What about the law," Arthur said dismissively. "I've made peace with the druids. And in case you haven't noticed, there haven't been any executions for the use of magic since –"

"What are you going to do about me?" Merlin interrupted. "I've just confessed to a capital crime. You've said before, magic is evil."

"You're an exception," Arthur said, gesturing at him. "Evidently you can use magic and remain loyal, though you'll need to work harder at keeping it a secret. Your heart's in the right place, anyone can see that."

"Arthur," Merlin said, quietly but implacably – and caught his king's attention again. "I'm just the only exception you've ever seen. Magic isn't evil, it just is – but people fear it, fear the consequences of breaking the laws of the Ban in any particular. Like those villagers who were going to murder the old woman with the horn. There are more – there might be many more like me, but you won't see that as long as you keep your father's laws and require your people to do the same."

The king looked at him, a frown drawing his brows together and pressing his mouth down. "I suppose I can't accept the proof of your claim while it's still illegal to present evidence to support it. Perhaps when we return –"

Reality crashed down around Merlin, shattering the moment into thousands of shards that all reflected what Merlin had seen of Arthur's death – the terrible belated realization of mortality widening the king's blue eyes in the vision – and he couldn't stop the harsh chuckle that twisted up his throat.

"I wish," he managed, to answer Arthur's puzzled-troubled look, "that you would have told me you knew. I could have–"

"I don't have the right to force your confidence," Arthur said in a low voice. Directly opposite to how he usually claimed, I have every right, I'm king. "I wasn't going to take the security of your secrecy from you, like that."

This time the expression of Merlin's morbid amusement felt and sounded more like a sob.

"But Arthur," he said. "If I wasn't keeping secrets so I didn't lose my place at your side, protecting you. I could have told you about Mordred, and about Camlann."

"Mordred made his own choice," Arthur stated, but couldn't quite hide his wince from Merlin – he knew that Arthur blamed himself as much as he did, for Mordred's abandonment of his vows as a knight of Camelot. "But what about Camlann? I never heard of the place before Percival mentioned it."

"I did," Merlin said. And couldn't help moving closer, to look deeply in his friend's eyes. "It is the place of your death, according to druid prophecy. I didn't try to warn you because you wouldn't listen if I couldn't explain –"

Arthur gave him a bleak look of shattered regret, maybe for his part in furthering the deception that came between them and prevented clear communication.

"And I didn't try to talk you out of it," Merlin continued gently, "because I know you, you don't hesitate to give your life for your people if that's what's necessary. I just – I need to try to get my magic back so that I… I can fight with you, when we go."

Arthur ducked his head in a nod, a wry smile pulling at one side of his mouth. "What happened? I didn't know it was possible for a person to lose his magic."

Merlin recalled the feeling of foreboding that had drawn him upright on his bed in the dark of his room, the silent sibilance of menace that had sobered him before the gean canach struck.

Horror – disgust – abysmal emptiness – more horror.

He felt Arthur's hand on his shoulder, and it pulled him back into the shape of himself.

"You better sit down," the king advised, and there was no amusement in his tone.

"Mordred knew," he heard himself saying.

"He was a druid," Arthur remembered.

Merlin's vision cleared to see Arthur seated facing him, almost knee-to-knee, leaning over clasped hands. He couldn't tell whether this was a recent realization, or if Arthur had known for some time. Or all along?

He nodded. "Mordred would have told Morgana about… my magic."

"Surely not," Arthur protested immediately. "Perhaps he could not stay here, after – that girl's execution, but he would not have gone to –"

Merlin's neck felt like it creaked, when he shook his head. "That's prophecy, too," he explained, feeling a fatalistic calm like the smooth surface of a very deep, very dark pool. "Mordred and Morgana, united in evil."

"Is that why you never liked him," Arthur said tiredly.

"I never trusted him," Merlin said, and realized it for a correction. He could have liked Mordred, if not for that bit of unwanted foreknowledge. "But once Morgana knew I had magic, she would have realized that –"

"She needed to go through you, to get to me," Arthur said grimly, straightening and sitting back. "And whatever magic they did –"

"Dark magic," Merlin said without meaning to.

Arthur paused as if to consider for the first time, the theft of someone's magic – the rape of someone's soul – a crime. He observed, "You haven't been yourself."

Merlin clutched his fingers to keep them from shaking. For so long his magic had defined him; though he sometimes wished he'd never had it, he'd also thought, if he couldn't use it he might as well have never been born. Now… he had helped Gaius tend the casualties of Stowell, and he had made all the preparations for the king's journey, without his magic. He was still himself – and the king had not turned his back on him.

Arthur sighed. "You threw yourself in front of the dorocha. You went with us to face the dragon. And you stood by me twice when Morgana tried to take Camelot. Merlin – I'm sorry I provoked you, just now. I didn't realize… What can I do to help you?"

Merlin's heart almost broke. What wouldn't he have given to hear those words, other times in their lives? When he'd said them to Arthur, the response was usually, Nothing; how can a mere servant help now. If he'd been able to seek help from Arthur… but he couldn't take anyone or anything away from Arthur's battle arrangements.

"I asked Gwaine to go with me, but I won't keep him," he said. "There's a cave, the birthplace of magic. I hope… if anything is to be done, it will be there. But it's in the valley of the –"

"Fallen Kings," Arthur said. There was a clear, sharp, thoughtful look in his eyes, though his gaze was directed over Merlin's left shoulder. "That place. Once I thought we'd lost you there for good – and you came stumbling out without a scratch on you. And once I thought I'd been gravely wounded – and woke up with barely a bruise."

Merlin inhaled, straightening and gripping the arms of his chair. If Arthur knew the one key piece of information – Merlin had magic, all along – there was so much more he could discover. Good and bad, and hard to explain. Would he question – and would his questions lead to doubts?

Arthur's intensity locked their gazes together. "It's not that far out of our way," he said. "I'd planned a campaign to clear the bandits out of that valley, before Stowell, but… It's too dangerous, even with Gwaine, I can't let the two of you go alone. We'll ride out at first light with the army, and take a troop through the valley with you – it's not that far from our path to Camlann."

His throat was tight, but he managed, "Arthur, you don't have to –"

"You have been there for me when I needed you," Arthur said determinedly. "And I have been both blind and ungrateful. Allow me to be there for you when you need someone?"

And that, was true friendship offered.

He felt both overwhelmingly humbled, and overwhelmingly honored. Hiding his overflowing eyes with his sleeve, he ducked his head in a nod, and felt Arthur's hand squeeze his shoulder.

"Now," the king said, in a tone that added, let's forget emotion and get back to action. "How about actually packing all this lot?"

…..*….. …..*….. …..*….. …..*….. …..*…..

Just half an hour after midday, and Merlin's stomach still nearly empty – he couldn't bring himself to swallow much – when Arthur nodded to Leon. The senior knight signaled the others, and along with Gwaine and Percival, they peeled away from the column, heading for the deeper forest that hid the Valley.

Gwen gave Merlin a look equal parts sympathy and encouragement as he followed his king. She'd expressed interest in accompanying them, early that morning before they'd departed the citadel. It still made his head spin, how quickly she'd gone from shock to gratitude, to hear of Merlin's erstwhile abilities. He wondered if she would have guessed also, before too long.

"Are we," Gwaine called forward, "far enough away from everyone else that I can ask, what the hell are we doing? Going here? now?"

Merlin darted a glance at Arthur; the king didn't look away from the path, but his lips quirked. "Vital supplies."

Gwaine snorted. Leon said, quietly concerned, "Sire?"

Arthur drew rein, pulling his mount's head sideways to block the path. Merlin's mare continued another pace before he reacted to halt her, looking over his shoulder as Arthur turned in the saddle to face his three knights. "Merlin has something he wants to tell you."

Merlin swallowed dryly as three pairs of eyes found him simultaneously. Now that Arthur knew – well, now he knew that Arthur knew – Arthur had advised and he had agreed, at least these three should know, also, as well as Gwen.

"I've used magic all my life," he said to them. "Before I came to Camelot, while Uther was king, up until this week. To protect Arthur. And the people."

Realization dawned in varying disconcerted degrees, memories resurfacing to be reconsidered, reactional prejudice checked.

And then Percival said, "Oh."

And all three looked at Arthur. Who said mildly, "Arrest him for immediate execution."

Merlin's heart lurched in momentary disbelief and fear, before he realized. Arthur was between him and the knights, facing them.

Gwaine's eyes narrowed. "You're joking, right?"

Leon did something with his reins that set his mount shifting its weight uncomfortably, as he looked from his king to Merlin, and back again. Percival was frowning in a puzzlement that made him look very young.

Arthur added, "We'll kill him and leave him here, avoid the trial and the gossip and paranoia of revealing my manservant as a sorcerer. He hasn't got his magic now, so we've nothing to fear from him."

Merlin's pulse thudded around his body with painful uncertainty.

"That's not funny, Sire," Leon said, faintly troubled. Gwaine was scowling – at Arthur - and gripping the hilt of his sword.

"What makes you think I'm not serious?" Arthur said, still in that same calm voice. Gwaine glanced at Leon.

Who answered, logically, "Because you still trust him. You've got your back to him right now. And he hasn't kicked his horse into a gallop to escape – he trusts you, too."

Arthur looked back at Merlin contemplatively – and he tried to appear more confident.

"You just wanted to see how we were going to react," Gwaine said accusingly.

"I did," Arthur answered, guiding his mount to continue. "I've known about Merlin for a while, now. His loyalty is unquestionable – which means I'm going to have some laws to revise when we return. But if I'm to have a chance at that, we've got to get Merlin to a cave in this Valley that will renew his powers. I wasn't joking when I said he hasn't got magic, at the moment."

Behind him, Percival realized, "And that's why we're along, because it's too dangerous a trip for him to make alone and unprotected."

"And why you had to see if we were going to protect him, after we knew," Leon added. Merlin risked a glance at him – he still seemed faintly troubled, but he was loyal to Arthur, too; he'd follow where his king led.

"What happened, anyway?" Gwaine asked, riding up on Merlin's outside flank.

"We think when Mordred betrayed his oath, he joined Morgana and betrayed Merlin's secret, too," Arthur answered for him. "She sent a magical creature – dead now, don't worry – to strip his magic."

"You've seemed a little odd these last days," Gwaine realized. "You all right, mate?"

Merlin smiled at him, thoroughly warmed by the word, and nodded. A bit dizzy, again, at how quickly these three accepted the truth about him – and a little sick to his stomach to remember how afraid he'd been that they might not. Or maybe he was just hungry, after all.

"Provided this works, whatever Merlin's got to do to regain magic," Leon said. "You plan on allowing him to use it openly at Camlann?"

"I'm sure Morgana won't expect him to be there at all, after what she did," Arthur said.

"I'm sure she won't expect me to be wielding magic right next to you, either," Merlin said. Somehow, as they all rode together, his uncertainty was settling into the conviction that this would work, that his magic would return in time for him to join battle with the witch, allied in evil with the druid boy – no matter what Kilgarrah said about fate and doom.

"I can't wait to see her face when she sees the two of you fighting together," Gwaine added, with a fierce exultation in his voice.

"Quiet, now," Arthur cautioned, lowering his own voice. "The Valley."

The warning came too late. Half a dozen ragged bandits erupted from hiding places in front of them – a second later, another contingent attacked the rear with full-throated battle cries.

Merlin panicked silently. Now it wasn't just his life and Gwaine's, in danger, it was Percival's and Leon's and –

Arthur.

Merlin drew the sword hung on his saddle awkwardly and slow – desperately – and swung at the two men who came at him. And lost his weapon to the second – jarring clang and numbing fingers.

And Arthur was fighting to keep his seat as three more bandits sought to pull him down.

A storm of emotion swelled up and out – anger and fear, agony and anxiety – an impossible dream, lately realized, now threatened. And he couldn't do anything –

Yes he damn well could.

Merlin yelled his feelings of frustration – and didn't stop. Under-after-following-towing-overwhelming came the magic.

Like a geyser from a dry well. He was too shocked for his usual control, and defense exploded from him, blasting each attacker back, bodily off their feet til they hit various trees and tumbled to the ground.

The mounts whinnied and danced. Merlin gulped and shook with reaction for a moment. Only a few of their downed assailants moved, and none rose.

"Holy hell," Gwaine said blankly.

"And that didn't even touch us," Leon added, and he sounded as shaky as Merlin felt.

Arthur checked all around them, before sheathing his sword and giving Merlin a brilliantly triumphant grin. "So it's back, then."

Merlin nodded dumbly. His magic felt like it was simmering down inside him, still hot and ready and full – but returning to its usual quiescence.

"You can't really lose what you are," Percival concluded thoughtfully, while Merlin's gaze was still connected to his king's.

And he thought – and he saw that Arthur thought, too – of a moment in a clearing not too terribly unlike this, not too terribly far from here. Metal in rock, and symbolism and confidence, re-claiming a possession, again accepting a privileged responsibility. Authority and power, and Arthur understood him.

"Come on, Merlin," Arthur said, fiercely eager. "Let's go to Camlann."

A/N: If I was a reader, I would not want this story to end here. But as a writer, I've done 'changes to Camlann', before, I don't want to repeat myself. Suffice to say, when details change, I believe the end result would change also. Morgana doesn't hear from Eira that Merlin and Gwaine are heading to the Valley, so she doesn't trap Merlin there. And if he can stand in the gap and throw magic around, then he can be at Arthur's side when Mordred reaches him…

Also, it's kind of a head-canon thing for me, that the cave doesn't really return Merlin's magic, as though he would have remained powerless forever, if he hadn't gone there. I think it's something that might take time to recover, and a level of confidence and faith in himself (that his vision of Balinor provides, in-canon). And maybe a whole lot of, if Arthur needs Merlin's magic desperately and imminently, it answers even without Merlin's conscious intent.

There's one more story, which might be 2 chapters – it isn't finished yet, so I don't know when it'll be posted…