Disclaimers: BBC's – not mine. No infringements intended.

A/N: Here it is! The Merthusa-version of Shapeshifter that I promised XAOTL Omega. The idea of the composition is that the two first chapters are almost identical to the original story save the last two paragraphs that are rewritten here below before the third chapter starts. The trick was to remove any of the I-feel-so-like-a-father Merlin that the original story contained. In my opinion, no healthy person who feels like a father would go for his offspring in a sexual way. Therefore, that feeling in him would have to be erased. Instead, I hope to convey a certain sense of responsibility in him, but rather that of a mentor, who might feel that an attraction towards a student is wrong, but could be swayed. Therefore, this story will be completely different with a different focus and a different ending. I have recycled some of the scenes, just giving them a twist that serves the new objective.

Stay away from this if you think the combination of Merthusa is just wrong, but read it if you like the idea. Those of you who do … please let me know how I have solved this challenge. :-)

A last warning: It might get smutty – I haven't decided yet.

xxx

"Heaven help us!"

The words were Gaius' and for once, Merlin couldn't agree more.

"That's what I was thinking," he grumbled.

"Merlin, you will have to lock her up!" Gaius said, emphasising every word, "she probably hasn't discovered it yet, but once those teenage hormones are raging, she will have no upbringing to help her ignore them!"

Merlin blanched. "Well – erm. I don't know anything about female hormones," he stammered, "You have much more experience in this field than I have, Gaius. What do you suggest?"

Gaius sighed. "Well, we are at a loss here. You and I have seen this issue from the other end and not hers."

Merlin nodded. "Gwen is coming round any second now. We could ask her to have a talk with Aithusa – well – as talks go with her."

"Not a bad idea," Gaius admitted. Then he straightened and looked at his protégée with something very like pride.

Gwen came by after supper, carrying a beautiful ash blue everyday dress for the new young addition to the Gaius household. She greeted Aithusa cordially and held up the dress, satisfying herself that she had got it exactly right. "You'll look beautiful in it," she stated and answered the girl's smile that was becoming increasingly less stiff.

Gwen felt a tentative hand on her elbow and turned to see Merlin and Gaius stare intensely at her. She cocked an eyebrow, recognising a silent plea. Leaving Aithusa in Merlin's room to finish her dressing by herself, she therefore returned to the laboratory.

Merlin started without preamble. "Gwen, could we ask you to … I mean … Aithusa's mother never got the chance to … and now she's ..."

"Menstruating?" Gwen suggested.

Merlin's eyes widened and his shoulders fell so quickly it was almost comical.

"YES! How did you...?"

"I saw the blood on the sheets in your room," Gwen laughed, "you poor guys. You really have got your hands full, haven't you?" then she turned to Gaius.

"Honestly, Gaius – you're a physician!"

"I can tell her about the physical part of it, as I have already provided her with towels," he grumbled, "but she has already read a whole book on it. It's the … do-not-run-after-boys-and-ignore-your-hormones-part we need you to convey."

"Oh," Gwen said and then frowned, "hasn't her mother already …?"

"No," Merlin said quickly, hoping to god he wouldn't have to explain this further.

Fortunately, he didn't. Gwen took it in her stride and said instead:

"Well, we'll take tea, thank you very much – and a biscuit and then I will return to your room and your cousin, Merlin."

Armed with her request, Gwen went back into the said room, leaving the men outside while they, perhaps for the umpteenth time in their life, were wondering exactly what women were telling each other when not in the company of men.

CHAPTER 3

Hormones!

The following days went a little more smoothly. Gradually, Aithusa was getting used to using the wash room, and slowly she was getting used to normal human food. She would, though, still throw a longing glance after the occasional critter or cat in the street and stand very close to Gaius or Merlin when they were cooking, her eyes hungrily focused on the piece of meat they had dropped in the pot or on the cook in question if the food be vegetarian. At unattended moments, Merlin would even catch her drooling despite the fact that he had cautioned her not to do so. It is not proper, he warned her. Why not? she wanted to know. Merlin couldn't quite explain it – it had something to do with decorum. And then he had to explain to her what decorum was.

Being the literal creature she was, she would then strive to stop drooling over meat – but not when he found her gawking at a handsome knight passing by in the street. At first, he thought with a shiver that she saw the person in question as a piece of edible meat, but later he realised that it was a different kind of delicacy she recognised in the knight. Again, the unfortunate sorcerer had to explain the proper manner to his ward.

But I see men drool over women, she argued. That may to be so, Merlin answered her, but the other way round is not proper; a lady does not drool over a man. She cocked her head, indicating that a question was on its way. Would you be offended if I drool over you? Merlin started, the very thought of it making him blush past his prominent ears. He hadn't even considered the possibility that she might actually do that.

YES! Don't do that, he cautioned her.

Later that day, fortunately, the issue of discussion had changed into the finer pronunciation of the human language. Gaius was being his most scientific self in his approach. "Aithusa, my dear, round your lips, use your midriff to press out some air in little huffs like this," Gaius said, squeezing out the letter o.

Aithusa frowned, looking at Merlin, who nodded his approval at her, and she eventually mimicked the sound nicely. Her success took her by surprise and she looked up and looked at her two hosts, who were cheering her along with huge smiles. In her eagerness to please and to follow up her good effort, she tried again, this time applying more force in the air huffing…

… which resulted in a torch of fire leaving her mouth with a hiss.

Impressively swift for such an old man, Gaius threw himself to floor, whereas Merlin made a very nice ballet move to the right, dodging her lethal flame by an inch.

"WOAH..." Merlin exclaimed, "a little less midriff, perhaps!"

Aithusa looked at them with regret in her eyes and two red spots burning on her young, smooth cheeks.

x

The midriff-fire episode was not without merit as it did leave the young dragon thoughtful as how to control that particular part of her body more efficiently. The next morning, Merlin found her crouching in the corner of his room with her right hand on her midriff, emitting vowels while trying to control her inner fire. She looked up, her glance beckoning and curious as the same time. Will you help me?

"Of course," he said softly, "what can I do for you?"

She rose, her lithe body only clad in her night shirt, and approached him. Then, without explanation, she turned her back on him, reached back with her right hand and grabbed his to place it on her midriff. Merlin suppressed his reaction brought on by the smell of her hair and her slightly moist skin. Her hand was cool, but the belly skin he felt through the shirt was quite warm. Are her dragon fires blazing already now? He asked himself.

When I utter a vowel, she projected, please hold in my diaphragm, she said, using the Latin term she had read in the book on human physique. If the muscle comes out after clenching, it will release the flames. It helps when I crouch, but I cannot crouch every time I say something.

Merlin had to agree in that, she felt him nod against her nape and knew he was ready.

Then she inhaled; Merlin felt how her powerful muscle contracted and he let his long, slim hand follow the movement. She then paused before rounding her lips, her guardian held his hand still to limit the midriff's movement as she exhaled, letting out an 'o' in the process.

Success! No smoke or fire escaped. He felt her exhale heavily in relief. Merlin kept his hand firmly on her diaphragm, expecting her fiery reserves to react to her sigh. The dragon girl smiled and leaned back, into his arms, resting her head on his shoulder, and flashed a genuine smile at him. Thank you. Then she straightened, touched his hand to signal that she would like to try again; Merlin pressed in his hand again, her belly now warmer than before, the flames inside of her rolling and feeding on her emotions. Aithusa concentrated, opened her mouth and uttered "tha yu".

Merlin laughed in triumph, delivering a quick and chaste peck on her temple.

"You did it," he said proudly, "you said a word!" The dragonlord hugged his dragon cordially.

x

Merlin's young dragon girl continued to practise her vowels diligently, yet this was not the only challenge she faced as a human. Coordinating the most intricate tool ever created by the Almighty proved to be more difficult than she had anticipated: using her hands to the extent of their innate potential.

Aithusa was sitting with a bowl, trying to peel pea pods; she didn't have much luck, which was obvious from the heaps of squashed and ripped pods round her chair. Merlin watched her affectionately: how she sat there with her dress drawn over her knees balancing the bowl between her pale, bare knees. This particular exercise had caused her problems too and had partly resulted in an excess of peas on the floor. Her eyes were reflecting deep concentration and her otherwise very smooth brow was knitted in frustration and effort as one pod after the other slid through her fingers and down onto the floor. Merlin's smile widened. She was so diligent and her tenacity appeared boundless. The warlock went to her side, picked up a pea pod and one more time showed her how to separate the pod halves from each other and take out the peas. She watched with deep fascination and awe and tried it again herself. A little better this time, yet it still left room for improvement.

It's a question of coordination, he projected to her the way he always did when she needed comfort. Eventually, your fingers will grasp the idea. She nodded obligingly and tried again. Still, though, her fingers weren't too keen on following her instructions. Merlin reached out, placed his long, sleek fingers over her feminine, elegant ones, gave them a little squeeze and said.

"Follow the movement of my fingers and you will soon pick it up."

Aithusa looked intently at her dragonlord's hands and concentrated on letting her own hands stay put underneath his. His hands were warm to the touch and hers were cool. As a cold-blooded reptile, her limbs would follow the temperature of her surroundings, being shade or sun. This constant extremities warmth was hard to get used to, yet the heat radiating from her master felt pleasurable and comforting, she decided. Shaking her head gingerly, she returned to the task at hand and finally managed to peel the pea pods correctly. Merlin's exhilarated reaction to the success made her warm inside – also a phenomenon that would not happen in her reptilian form.

x

As the days went by, the dragonlord noticed a growing frustration in his dragon. She simply found that she did not progress at the speed that she would like to. Merlin sympathised: Humans required years develop their skills. As almost any other species, she would learn in no time, however, while Aithusa was in her human form, patience was one skill she would sorely need. Patience and … time off. This gave him an idea.

In the middle of the night, Merlin took Aithusa to the place where he used to meet her dragon mentor, Kilgharrah. The place was not too far, well hidden and perfect for landing and taking off and would thus be a nice spot for the young white dragon to stretch her wings and be … a dragon.

"Well, shapeshifter," he murmured, stroking her cheek, "spread your wings and have a ball. We don't need to go back until early daybreak."

Aithusa flashed him a toothy smile and quickly shed her clothes completely devoid of modesty to her ward's consternation, leapt forward and spread her arms that fluently morphed into wide, leathery wings. Fascinated, Merlin watched as the rest of her was transformed into a dragon to fit the wings and for the first time, Merlin actually set his eyes on the full grown form of the white dragon Aithusa. It took his breath away.

Her scales glinted white in the faint light of the half moon, her eyes, still watery blue, blinked at him the way he remembered when he called her into this world. Her brow and nose ridge were slightly aquiline, her limbs slim and long and her tail longer than that of Kilgharrah.

"Amazing," Merlin sighed, "the last time I saw you as a dragon ..." then he frowned, suddenly remembering an interesting fact from back then. "The last time I saw you as a dragon, you were a boy dragon."

Aithusa nodded, this human movement now so integrated in her that she used it too in her dragon shape. That is true, my dragonlord, she projected, when I realised I was the last of my kind, however, I changed my sex.

Merlin looked at her, bewildered. "How can you do that?"

It is not uncommon even in non-magical beings, she pointed out, some of my distant amphibian relations can do this when our species is in need of breeding.

Without further comment, the white dragon bent her legs and her heavy body lifted itself off the ground, quickly flapping the large wings and within seconds reached a high altitude.

Merlin laughed out loud as he saw how she playfully threw herself into the air, making one loop after the other, expressing sheer joy of life, diving quickly towards the ground only to break off in the last nick of moment and then rising vertically towards the stars. Had she not been white, he would have had a hard time following her flight in the night. This was her true self, her real nature; she was in his household on loan, only – he would lose her company one day.

Merlin sat down on a stone and watched her, thirstily drinking the sight of her every move. He was so enwrapped in the sight of her breathtaking flight that he didn't even noticed her landing in front of him, transforming back into a human; she knelt by him. "Up … 'ere?", she said, pointing up. Still being somewhat rosy cheeked by the sight of her beautiful naked form, he smiled, embarrassed. "I would love to. On your back?"

"No," she said, getting up and wrapping him in her arms before he could protest. Her back morphed into a dragon's strong spine and powerful wings, complete with tail for rudder, but her front stayed human as she easily lifted herself and Merlin into the air. Wrap your arms round my waist, she projected. She didn't have to say that twice. Merlin was holding on to her for his dear life, burying his face in her long, white golden hair. Sufficiently high up in the night, she flipped and proceeded to fly on her back, Merlin now lying on top of her, secured by her long, strong arms. The lower part of his chest lay against her warm belly of flames and kept him reasonably warm against the chill of the black night. The wind tore at his raven hair and sculpted face, making his eyes water and he found it hard to speak. Is this not cold for you? he projected, is the dragon form not better suited for a cold night?

My inner fire keeps me warm from my scalp to the tiniest of my toes, she answered, peering up at him with her transparent eyes that, at that moment, looked like a window to the universe with a thousand little stars twinkling their reflection in them.

I don't ever want to get down, he found himself thinking. Yet, of course, they had to. Dawn would be breaking shortly and a day of duties and responsibilities were waiting.

But they would be back in the air. Oh, yes, they would be back.

x

Walking home by daybreak, the red sun only just beginning to peer over the horizontal line, Merlin keenly felt how relaxed the nightly excursion had made Aithusa. They were passing through the slowly awakening town, Aithusa lively and energetic and Merlin tired to the bone having been bereft of his much needed sleep. But it was worth it, he thought, I am sure this will prove to work wonders on her tension and it will be much easier for her to concentrate on learning how to speak and to ignore her hormones.

Engulfed in what he hoped and believed to be prophetic musings, he never noticed how Aithusa's head suddenly whiplashed to the left, her eyes very attentive and her smile very predatory. Her pheromonal sense picked up the seductive movement and masculine musky scent of someone who was very much a man. This particular man was just coming out of a tavern where he had spent the entire night, his long limbs dangling in a rogue and suave way even if he was stone drunk.

Aithusa had just spotted Gwaine.

xxx

Jealousy next? The only way you'll find out is if you stay tuned! Let me know what you think, please! Review, review, review! PLZ!