His flat wasn't made for dogs to scramble into. Narrow halls, books piled here and there, a forest of herbs by the window but Arthur didn't seem to care. His paws clicking against the wooden floor, he lunged in, began to sniff around, apparently loving all the smells.

A dog's way of finding out who was friend or foe, but Arthur wasn't a dog, at least not yet.

Morgana's taunts returned to haunt him. If what she'd implied was true, Arthur had little time left before he was a dog and nothing else.

Merlin wasn't going to let that happen, not after waiting so long for Arthur's return.

But for a moment, he just stood there, trying not to think, trying to just revel in the sound of Arthur's enthusiastic explorations. His king was back, his friend was back, the man he loved the most in all the world, for all the ages, was back. It didn't matter that he was a dog. Merlin's long wait was over.

With another woof, Arthur nudged into his hand, bringing him back to worried blue eyes.

He knelt down, ruffled Arthur's fur. "I know you think I am some kind of all-powerful sorcerer." At that, Arthur sent him a look of utter disbelief; somewhere in there was a quick doggy sniff, too, a bit of an insult if memory served correctly, but Merlin ignored it. "I never thought to learn the spell for dog speech. So we will do it the old-fashioned way."

When Arthur tilted his head looking confused or annoyed – Merlin couldn't quite tell, he just sighed. "One nod for yes, two for no."

Merlin didn't realise that dogs could roll their eyes like that. In some ways, the doggie Arthur was far more condescending than he remembered his prat being. But as Merlin stood up, Arthur bit down on Merlin's sleeve and pulled him further into the flat.

Trying not to fall over as he was tugged along, curious to see where Arthur was taking him, he just went with it. "So I guess that's a no on old-fashioned."

As Arthur let go, with a final contemptuous sneeze, he nudged Merlin closer to his computer. Then climbing up on the chair, taking up a pen in his mouth, he started poking at the keyboard.

It took a while but Merlin was willing to wait. They'd be able to communicate, at least until he could find something to change Arthur back.

On the screen, it read 2 dasy.

Merlin bent down, looking first at the screen and then Arthur. "Two days until it's permanent?"

Arthur nodded.

Two days wasn't nearly enough time. He'd have to find the correct spell, gather whatever supplies he'd need – and that usually meant extremely difficult and rare herbs because when was anything ever easy, make up the potion which sometimes took days to steep properly, and then hope it would work. Damn.

But he didn't say any of that to Arthur. He was probably upset enough. Instead, trying to seem confident and completely in control, Merlin said, "How do you know? Did Morgana say something?"

His eyes narrowing as if he could read Merlin's mind, dropping the now wet pen beside the computer, Arthur gave a little woof. He nudged Merlin forward, using a cold nose to do it, and then patted at the keyboard with one paw.

He wanted to lie to Arthur, reassure him but those blue eyes were boring into his own and he couldn't. He'd lied to Arthur too many times and it only ever made things worse.

Finally, giving a long, drawn-out sigh, trying and failing to postpone the inevitable, he said, "Off the top of my head, I don't know how to fix this, Arthur. I will try as best I can. Transformation spells are ridiculously convoluted and sometimes the wrong cure can only make things worse."

Arthur growled a bit, then picked up the pen again. "speek yu fx."

"If I try and find a spell for dog speech…, Arthur, it will take some time." There was a little growl deep in Arthur's throat, annoyance or frustration, and for the thousandth time, Merlin wished Arthur could talk. Much as he could be annoying, Merlin had missed the banter, missed the ridiculous ordering about, missed Arthur's teasing as well as his bravado in all those years of waiting. Missed Arthur so very much.

But there wasn't time for regrets and what-ifs. Arthur was in a terrible position, and had Merlin been transformed like that, he'd be over-the-moon anxious to free himself. Dogs were loyal and great companions but Arthur wasn't meant to be one. And if Merlin didn't get his head on straight, the man he'd waited for all those years would be doomed.

Another cold-nosed nudge and Merlin gave up. "I'll try to find one. I'll give it an hour, no more, then it's transformation spells. I can't risk missing the deadline, not over something so trivial."

A yip, short and pointed, and Arthur was already jumping off the chair, wagging his tail as Merlin sat down and started typing away.

Even though he didn't have the books that Gaius would have had at his disposal, still with the advent of the internet, he could search for anything that had been scanned into the web. It was a thousand times easier than spending days in Geoffrey's cavernous library but still, so much had been lost over the years, especially magical information, that it would be difficult to find just the right spell.

And it proved frustratingly tough.

Merlin would have thought that finding a translation spell would be easy enough. He hadn't needed it before, but the magic should be straightforward, to take Arthur's growls and noises and translate them into coherent speech. Simple.

His concentration was shit, though. His worry that he'd not be able to change Arthur in time was blocking him a bit, setting his mind adrift towards all the ways it could go pear-shaped. It didn't help that Arthur was roaming the flat, poking into everything, sniffing around, pushing books and plants aside, chewing on one of Merlin's shoes, his tail-wagging an ever-present danger.

Finally, concern ratcheting up and up, when Arthur's playful exploration sent a tower of books crashing down and chipping one of his more cherished possessions, a clear stone from the Crystal Cave, he didn't think, just shouted, "Can't you sit still for one moment? I need to…." And then he stopped when he realised that he'd been yelling at the one person who didn't deserve his anger.

There was near silence on the other side of the room. No tail wagging, no growls of annoyance, no howling, nothing but a too-low-pitched whine of apology. When Merlin turned around, he could see Arthur cowering a bit behind the sofa arm.

His heart sticking in his throat when he saw him there, a furry ball of contrition, Merlin wanted to cry. He hadn't done that in centuries but seeing Arthur brought so low was difficult to bear. And worse, it seemed more a dog's response than Arthur's. The human side would have blustered through, would have said that as king, he could crash into things or break things or make as much noise as he wanted. But the dog's reaction was to hide from his master's wrath.

He couldn't take the time to try and make things right, but he did anyway. To see those blue eyes so close to tears just hurt.

Kneeling down next to Arthur, throwing his arms around the dog's neck and murmuring apologies, Merlin said, "I'm sorry. I'm just so… I don't want to fail you, not now. I'm sorry I yelled."

Merlin stayed there a moment, trying to calm down enough to think, when he felt a warm wet tongue licking at his ear.

Not exactly how he planned on Arthur kissing him, those dreams were long gone, but Merlin really didn't want a dog's long tongue licking him like that. It was unsanitary, and in some ways, kind of sick. He'd wanted so much more from the human Arthur and this almost felt a betrayal. Or not. Did a doggy lick count as a kiss or was it just excitement or apology?

Merlin was very confused.

Letting go, catching Arthur's fur in his hands, he pushed back a little. Arthur gave him another lick right across his cheek. He couldn't help it. Confused or not, it tickled and Merlin gave a startled giggle instead, and then felt ashamed for laughing.

He sat back, keeping the dog at bay. "Arthur, I know you are bored. I know you want to run and go hunting and chase rabbits and maybe yell at me for taking too long, but I need to concentrate. So how about I get you something to eat and when you are done, we'll go for a walk so… you know." He pointed down to Arthur's nether regions. After all, it had been a while and dogs do have to pee from time to time.

His tail wagging again, Arthur gave a little yip.

That was good enough for Merlin. Getting up, he went over to the fridge and looked in. There wasn't much there and certainly no dog food. He'd have to think about that later. But there was some leftover chicken, pizza that was only a day or so old, and a bunch of vegetables.

Pulling out the chicken and the carrots, he chopped them up a bit, making sure there were no bones in the mix, then put it in a bowl and placed it on the floor so that Arthur could get to it easily.

Arthur sniffed at it a moment, then looked up and scowled at Merlin as if waiting for him to fix it.

"Sorry it isn't up to your exalted standards, sire, but we peasants have to live a bit more simply these days."

But Arthur shook his head, then used his nose to point to the table. When Merlin just stood there, Arthur closed his eyes a moment, then stared at Merlin, giving him one of those I-have-to-put-up-with-your-idiocy looks, pushed the bowl a little toward the table, and hopped up onto the larger of the two chairs.

Apparently, Arthur wasn't dog enough to eat on the floor, not yet.

Merlin had to admit he was rather relieved.

Once the bowl was empty – Arthur had quite an appetite and Merlin knew he'd need to buy more supplies soon, he poured out some water into a second bowl, then gave him a head pat as Arthur eagerly lapped it up.

Giving a computer one last longing look, sure that the answers were in there somewhere, still he couldn't let Arthur pee all over his floor. It wouldn't be good for the wood, and more importantly, he didn't want to embarrass him. So, giving a little sigh, he said, "Time for walkies, sire."

If looks could kill, Merlin would have been bones already. Apparently, doggie talk was not acceptable. And frankly, Merlin agreed. It had come out all on its own. He hadn't even thought about it, just went with what he'd heard on the telly. All he could do was apologize and nod toward the door.

"Sorry, Arthur. It… okay, you need to pee and I need a walk so if you are ready?"

Giving him another glare, Arthur looked pointedly at the loo. But him scrambling up onto the toilet could be a problem, and Merlin wasn't sure it wouldn't be more embarrassing for Arthur, never mind the potential mess.

Arthur had other ideas. With a sharp bark, he pulled away and walked, tail high, nose in the air as if offended by any suggestion that he was less than capable, into the loo.

Nosing the seat up, he stood on his hind legs, his front paws onto the top of the toilet, and started to pee into the bowl. Not missing, not even a little.

It was kind of amazing actually, especially when he finished and hit the flush lever. He turned around, looking smug, and gave a self-satisfied yip.

Trying hard not to laugh, his grin wide on his face, Merlin said, "I had no idea dogs could do that. I thought you'd have to pee on a tree or something."

If only Arthur could talk, Merlin was sure he'd be berated within an inch of his life. As it was, eyes narrowed, teeth bared a bit, Arthur gave a little growl, then an indignant sniff. It would have been funny if things hadn't been so dire.

Merlin threw up his hands in surrender. "All right, all right. I made a mistake. I make them sometimes, you know. It's not like I'm a mind reader."

Arthur didn't seem to think that Merlin was apologetic enough. Had he boots, he'd have been stomping back into the lounge. As it was, the stiff tail and raised fur was a hint that maybe Arthur was still miffed. He certainly refused to look at him.

But it didn't matter because Merlin was standing there, staring at nothing, thinking hard. He'd finally realised where he'd gone wrong. He didn't need a spell for speech. He needed one for reading minds.