A/N: Hopefully you are all wondering what Chris has done to himself at this point.

Part Four

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A minute or so later, Chris stumbled as he dragged himself into an upright position, waiting for his blurry vision to become crystal clear as his eyes adjusted to this new-found clarity. Checking his heart rate and temperature, he then added to his notes, and considered his next move. Faint murmurs filtered down from the party above, and he knew what to do but not dressed like this. Oh no, this wouldn't do. With a ferociously scornful act, he tore off his clothing and stood panting with exhilaration. Now this was living!

There was an air of satisfaction as he examined himself re-booted and suited. With a whoop of joy he raced out of the door.

Donna noticed him as soon as the stranger stood in the entranceway. In fact he deliberately framed himself there in the entrance, draped in a nonchalant pose to optimum effect. He was tall, dark and handsome; dressed in a carefully cut blue suit, with a brooding dangerous melancholy air about him. Everything screamed 'confident' about him though, from his precisely coiffured hair that sprouted from his head down to his shabby chic burgundy Converses that matched his tie. His dark brown eyes swept momentarily over the room as he looked for his prey, and then he pounced; aiming for meek Michaela as she stood waiting for her fiancé.

He entered the room only dimly aware of the crush of people there or the strobe lights that were broken by the flailing forms of people dancing. All of his senses pointed him towards a woman that smelt familiar. She wasn't exactly what he wanted, but she would do for now. Somewhere in the back of his mind was a voice that supplied the name: Michaela. But logic wasn't playing a massive part of his movements as his body made a beeline for her. Without making a conscious decision, he reached out and grabbed her upper arms, intent on possessing her as soon as possible.

"Get away from her, you letch!" Donna shouted at him as she marched up and wrenched his hands fiercely away from Michaela's arms.

Gobsmacked, Chris released the woman, instantly forgetting her, and regarded this feisty ginger vision in front of him. Her straightened hair hung loose around her bare neck to her shoulders, just as he liked it. That led his gaze downwards to take in the figure hugging rich wine coloured dress that emphasised every voluptuous curve. The whole effect made his blood fire with delight, and his eyes instantly teared up as he took her in, shaking his head in wonder; taking a deep breath to taste her scent. Oh yes! Now this was miles better. Every ounce within him suddenly wanted her as desire pulsed through him with a vengeance.

"Ooh, Donna Noble! I've waited such a long time for you," he softly crooned.

"You what?!" she demanded to know, in shock. "How do you know my name?" In her bewilderment she had totally missed him placing his hands on her waist.

He slowly aimed his grasp on Donna's body to pull her tight against his chest, and then eased her into dancing a few steps with him. As he had completely expected, she followed his lead across the dancefloor. "I know you like I know myself; we complete each other. With every breath I thank god I know you, right down to my very soul."

"That's a bit rich, ain't it?" she scoffed self-deprecatingly. He must have thought she was born yesterday, trying out a line like that.

A slight smile played about his lips. "Would you believe me if I said Chris told me your name," he offered instead.

Donna chuckled. This sounded more plausible. "Yes, I can do that. And who are you?"

He hastily looked around the room for inspiration as he sought an alias. "I'm Doctor John Sturgeon; but I'm generally called the Doctor."

"Are you now?" she wondered, slightly disbelieving him. "And how do you know our Chris?"

"Wouldn't you like to know?" he schmoozed into her ear; all the time guiding their dancing footsteps. "We share a lab together," he whispered closely, hoping his puffs of breath on her skin were having the same effect on her as her scent was having on him.

"In what way?" she tried to ask, but when she moved her head those lips of his were dangerously near her own; and they were extremely tempting. "And how come I've never heard of you?"

"I'm brand new here today," he replied in sultry tones. "But I've known Chris for some time."

"How come he didn't mention you were going to work with him?" she asked suspiciously.

"He was unaware I'd appear today," he told her with a smirk. "Here I am! And I couldn't wait to meet you!"

Donna snorted in disbelief. "I dread to think what he's said about me then."

"Oh Donna! If you only knew," he remarked as he led them into more dance steps; sweeping her across the dancefloor. "You want to know, don't you?" he teased when he caught her eye.

"Do you really expect me not to? Do be serious!" she scoffed. "And it doesn't seem fair that you know about me but I know nothing about you."

"Let's go find ourselves a quiet corner somewhere, and then you can ask me whatever you like," he offered; but he didn't wait for an answer as he started to lead her off the dancefloor and towards the exit.

Once out in the corridor, he opened a nearby door and found a small office. "This will do," he commented, and drew her in.

"Well?" she immediately asked defensively when the door shut behind them. It wasn't that she felt in danger exactly, but it never paid to be alone with a stranger despite how charming they can seem. Not that his charms were working on her in the slightest, or that she quite fancied the idea of being kissed by him; oh no. "What sort of relationship do you have with Chris?"

That smug grin appeared back on his face. "We're like that," he said, lifting up I his hand to show his first two fingers entwined. "In fact we couldn't be closer."

"Close enough to have your photo sitting on his mantelpiece," Donna remarked, not believing his story for a second.

The Doctor merely dismissed that remark with a wave of his hand. "Those photos represent the ones that got away, his wish list before he met you. If he were to add new ones… well, I think we can safely guess who would appear."

"Can we? Cos I can't," she replied. "Unless you mean Natalie in his department; he seems to like her a lot."

The sound of the party could easily be heard through the wall, providing a musical backdrop. "Why are we talking about Chris when we should be talking about us," the Doctor practically purred at her as he stepped within her personal space. "Dance with me," he softly ordered and took hold of her body again, as he swayed them in time to the music.

What was she doing? She found herself complying when normally she'd have slapped him one for his impudence. "Us? There is no 'us' to discuss," she retorted.

"Oh I think there is," he insisted as he rested his head against hers. "I can sense that you want me and I certainly want you; so no denying it."

Mesmerised, she gave him a look that clearly questioned his sanity. "How can you sense that?"

In answer he licked languidly up her neck and then gazed into her eyes. "Your heart rate is elevated, adrenaline increased, pupils dilated, and your pheromones are just kicking me in the palate." He then smoothed both of his hands down her back and landed on her bottom, gently crushing her lower torso as he lovingly caressed her body. "And there is part of your evidence. I can provide more if you like," he crooned.

"More? What sort of more?" she heard herself stupidly ask.

He leaned in and closed his eyes as he ghosted his lips over her mouth. "I was thinking of something like this."

One of his hands was travelling up her back as she answered, "That would do it." Going for broke, she flung her arms around his neck and pressed forward, allowing him to kiss her properly.

It wasn't the kiss she would have expected, all demanding and intrusive. Instead it started as a soft press when he landed delicately on her lips, as if he could hardly believe it was happening for a moment. Then he moved over her lips, savouring every second before opening more to taste her mouth. When his tongue met hers and slid over it in an intimate dance, she wanted to claim him, body and soul.

Breathless, they finally broke apart, dazed by the encounter.

"I think we'd better go back," he whispered. "Otherwise I won't be able to control myself for much longer."

"So that I know what I'm avoiding, what exactly are you in danger of doing?" she couldn't help asking.

He let out a feral growl that had far reaching effects on her libido. "Right this second it involves ripping your knickers clean off, and I have a feeling you might not welcome that later on the way home."

"True," she agreed. "In that case we'd better go and get ourselves a drink before we do something stupid."

The rest of the night was mainly spent wrapped around each other on the dance floor avoiding anything more complicated than the odd peck. Donna's hopes regarding their journey home were dashed when the Doctor suddenly shuddered and announced, "I've got to go. I need to pop down to Chris' lab for a while, to see how the experiment is progressing for a few hours." He then cradled her head lovingly, and told her sincerely, "We'll meet again, very soon, Donna Noble. I have every intention of finding you to continue our tryst. Don't forget me."

"I won't," she fervently promised.

He kissed her once more and ran, leaving her standing there alone but not feeling lonely. After all, he had said he would return, and she had every faith in him that he would keep his word.

After some minutes, Michaela approached her cautiously, and asked, "Who was that bloke, Donna? He came across as a bit intense."

"He was a bit," Donna had to agree. "He is Doctor John Sturgeon, and he's the new bloke in Research."

"I got the impression he was more than keen on you." Michaela gave her a playful nudge. "When are you seeing him again?"

"Soon, very soon," Donna answered confidently; and she relished that feeling.

The Doctor raced down to the laboratory. Oh, this didn't feel right. Everything was wavering, making his insides quiver and setting his nerves on edge. What he obviously needed was another dose of the potion. Yes, that should fix this until the sonic screwdriver was finished. Panting, he entered the lab and looked about hastily as he gained his bearings. The book that Chris had recorded his reactions in sat on the bench waiting for his input to update the data. The Doctor wanted to laugh with barely disguised disgust. A true Time Lord would not need to keep such notes; only a half-breed idiot would need all that. And in his opinion Chris was the lowest of the low, a paltry human wannabe.

As he went to laugh again a pain gripped him in his stomach, and he collapsed on to the floor. If he could only make it to the sofa in the corner, he could work this problem out…

Crawling on his hands and knees, a wave of deep fatigue hit him. So much to do, so little time. Easing himself on to the soft cushions, he only had time to think that he hoped Donna got home safely when he went out like a light, plunged into slumber. The next sound inside the lab was gentle snoring.

Several hours later he was woken by the ringtone on his phone telling him to get off his lazy arse and answer it. Reluctantly he lifted the device and saw that it was Donna ringing him. Smiling broadly, he pressed the 'receive call' button.