Part 1: The Trouble with Imagination

Arthur knew Merlin had magic.

Not because the idiot had told him – his servant was still mum on the topic. No, it was because Arthur had put his impressive skills of deductive reasoning to the problem that was his servant and finally figured the mystery out.

Or so Arthur told himself when he decided his ego needed a boost.

The truth was, Arthur had known for a long time there was something strange about Merlin. He got ordinary chores done impossibly fast; he claimed to spend time drinking yet never came back drunk – usually breathless and sometimes acting wounded instead; and most incriminating of all, he still tensed whenever magic was mentioned as something bad. Arthur had tried to gloss over all this – he really had. But the fact that his servant was strange remained. The fact also remained that Arthur felt deep down he had a pretty good guess as to why – and he didn't want to face that guess.

He had finally decided one night to sit down and ask himself what would happen if Merlin had magic – in the theoretical, of course, because there was no way his bumbling, clumsy servant (friend) was a sorcerer. Just to be thorough and go through all the possibilities, though, what would he do if he someday discovered that someone like Merlin had magic?

His first instinctive reaction, of course, was that magic was wrong, always wrong, always twisting the user, and he'd have to kill the perpetrator – regretfully, of course, if it was someone like Merlin, more as a precautionary measure against their becoming evil than because they already were. And he'd probably find a way to do it mercifully, not hand them over to be burned at the stake.

No sooner had he thought that than he had a horrible mental image of Merlin's face, twisted in agony and wreathed in flames at the stake. He shuddered violently and knew that option number 1 was knocked off his list – he could never turn Merlin over to his father.

He considered option number 2: a merciful death. And his imagination, which had decided to be annoyingly overactive that night, promptly provided him with an image of Merlin lying on the stones, his face frozen in a look of stunned betrayal, bleeding from a fatal wound in his chest.

Arthur shuddered and discarded that option too. There was no way he could kill Merlin or order him killed. He'd never be able to forgive himself.

On to option 3: banishment. And now he was imagining his chambers without Merlin there, with another servant instead who would keep them in perfect order and never call him a prat or a clotpole, who would never be annoyingly cheerful, who wouldn't always, always be there, faithful to Arthur, believing in him even when he didn't believe in himself.

What was it with his imagination tonight? Arthur got up and paced, frustrated. No sooner could he come up with a reasonable answer to the magic question than he realized it wasn't an answer he'd be able to live with.

What if he faced the idea that magic might not always make its users evil? What if it was a tool like a sword, either good or bad, depending on the wielder? He didn't want to face that option any more than the getting-rid-of-Merlin options, because if that was the case his father would be wrong and – and his purge would have killed so many innocent people. But bebother it, he had decided to make up his mind tonight on what he would do if Merlin theoretically – theoretically, mind you – had magic, and make up his mind he would.

He tried to imagine Merlin becoming evil, the power he had corrupting him, and this time his imagination refused to oblige. That frustrated him immensely, considering how hyperactive it had been before, but an evil Merlin wasn't something his brain could even handle. He could come up with plenty of examples of evil magic, of course, but he suddenly began wondering what he would do if he was a magic user and hadn't gone evil. He'd lie low, probably, try not to bring Uther's attention to himself, which meant Arthur as the prince would probably never have met anyone like that.

Unless Merlin was one of them, of course. In which case his servant was more of an idiot than ever, to be living right under Uther's nose.

Having more or less concluded, by elimination of all other options, that Merlin wasn't evil and that he'd be allowed to go on living as he always had even if he did have magic, Arthur turned himself to figuring out if he was actually right about the reason for Merlin's oddities or if he had sent his imagination to town for no real reason. This required paying more attention to Merlin than usual and keeping an eye on the oddities instead of dismissing them. It also meant some sneaking around, trying to catch Merlin doing chores too fast.

It took him longer than he had expected; for all his servant's behavior was suspicious enough to alarm him in the first place, he was surprisingly careful and good at keeping his magic hidden – if he really did have it. Arthur was beginning to doubt that he had actually diagnosed the problem properly in the first place – which was a decided blow to his ego – when he came back to his room one rainy day more quietly than usual to find the mud he'd tracked in earlier disappearing from his floor and a flash of gold in Merlin's blue eyes.

The discovery shook him more than he'd expected.

He said nothing to Merlin then, though, because what was there to say? He'd already decided Merlin could stay. And now he suddenly found himself hurt that he'd had to find this out on his own – that for all the years he'd thought Merlin was his (best) friend, Merlin didn't trust him enough to tell him.

He spent a few days sulking as he worked through this, before his imagination came to his rescue again. This time it conjured up images of living in a kingdom where magic was punishable by death, serving the son of the man who enforced that law, afraid for his life every time he let his eyes flash gold. Arthur promptly remembered that even he had considered letting Merlin burn for a moment, and shuddered. He understood why Merlin would keep it a secret.

Very well, then; he'd wait. Merlin would surely tell him someday, and until then he'd keep his servant's secret for him.

The next time they rode out against a magical threat, though, and he suddenly lost consciousness (a falling branch off a perfectly live and healthy tree, Merlin? That's the best you could come up with?) and yet returned to Camelot in victory, Arthur had a much better idea what had actually happened. He was feeling rather smug that he could actually guess what had happened this time, in fact.

He also realized it had not been his imagination how many branches dropped on his head just before battles with magical creatures. He was less pleased with that and wished Merlin would find another way of not letting him see magic that wouldn't be as annoying or give him as many headaches.

Things went on as normal for a depressingly long time. Arthur became king, and promptly relaxed the purge, and still Merlin hadn't told him anything. Arthur was beginning to wonder if he would have to confront Merlin someday, and that rather shook his faith in his servant.

There was a sighting of a griffin about a month into his reign, and he and Merlin and the knights promptly rode out to deal with it. They were getting close, as evidenced by the roars they were hearing, when Arthur happened to glance up and saw a branch – a perfectly good, solid, green branch – letting go of its tree right above his head.

Well. It was going to be one of those days, then.

Later Arthur would argue that he had had one too many branches dropped on his head, and Merlin should have known he had a breaking point with that; and Merlin would argue back that yes, he'd had one too many branches dropped and it had addled his wits at last. Arthur would ask whose fault that was, and Merlin would retort that if he had more wits in the first place he wouldn't have been in danger of losing them.

Whatever the reason was, what happened was that Arthur woke up in camp after the battle with a throbbing headache and knew exactly what had caused it. And he was tired and annoyed and had he mentioned he had a headache?

Merlin came over at once when he woke and knelt beside him. Later Arthur would realize there the look in his eyes was guilt as he asked softly, "How are you feeling, sire?"

At the moment, Arthur had only one thought on his mind, and he nearly shouted it.

"Will you kindly stop knocking me out, Merlin!"

Everyone in camp stopped what they were doing and stared at him in confusion. Merlin's eyes were wide. "I don't know what you mean," he started to falter.

But Arthur was sick and tired of being bonked on the head. "How hard is it to understand, you idiot?" he snapped back. "Stop dropping branches on my head! I know you don't want to show your magic and I get why you're afraid, but could you choose another way to try keeping me oblivious than giving me a headache every time I wake up!"

Now everyone's faces were an odd mix of confusion and shock. Merlin had gone white to the lips and rocked back on his heels as though Arthur had struck him. Wondering why everyone looked like that when he'd just voiced a reasonable request – forcefully, true, but the request was still reasonable – Arthur parsed what he'd just said in his throbbing head.

Oh. Oh. He'd just revealed he knew about Merlin's magic and revealed him as a sorcerer to all his knights.

One of those days, indeed. How was Arthur supposed to get out of this?

A/N: I know there are hundreds of similar fics out there, but I've been reading too many of them lately, apparently, and the idea of Arthur waking up and snapping at Merlin to stop dropping branches on him wouldn't leave me. So I whipped this little fic together. Hopefully you've enjoyed reading it as much as I enjoyed writing it!

There will be a part two coming soon, with the fallout from this. Stay tuned!

Also, obviously, I don't own Merlin.