Karina did not even flinch at the news of her family's demise.

The alien masquerading as a human woman smiled back at Peter as though it was he who should have been affected by what had happened and that he was being foolish in expecting her to become aggrieved over such a loss.

"Are you expecting me to cry again?" She teased. "Oh, Peter. That was all just a bit of fun. I do like to have fun, you see."

The Doctor spoke up before Peter had a chance to respond.

"Is that what you call it?" He questioned. "Stealing faces, stealing lives…. If that's your idea of fun, Karina, then we have a problem."

Karina's eyes positively sparkled as the Time Lord stepped forward. With his hands tucked casually inside his coat pockets, he stopped just short of reaching her and Peter.

"Who are you?" She questioned. "You smell old and dusty."

"He's a Time Lord!" Karugon called out. "Kalagan said that -"

Stefan swiftly cut him off as he grabbed hold of the alien and pressed the barrel of his gun into his back.

"Shut up!" He ordered. "Not another word."

But Karina had already heard all that she needed to. Cackling with delight, she turned back to the Doctor.

"I thought you were just a myth? But I can hear the two heartbeats now." She marvelled. "Did Kalagan try and go after you and your form?"

"Through me, yes," Peter informed her. "It didn't end well for him."

"No, I suppose not." She admitted. "Kalagan never quite thought things through properly. When he said that he'd killed the man he'd transformed into and brought down the other human down here, I knew there would be consequences."

Rose wondered if this was Karina's way of apologising. Was there a chance of at least one of these creatures showing some remorse for what had happened?

"Where is Jane Wilson?" Peter questioned. "Is she still alive?"

Karina considered the question carefully.

"What if told that she wasn't? Would you kill me?"

Peter raised an eyebrow at the challenge.

"I killed Kalagan in self-defence and all the other members of your family died trying to murder innocent people. They attacked my men and were put down because of it." He told her. "But if you surrender yourself right now, no further harm will come to you or Karugon. You have my word on that."

But Karina seemed to have suddenly lost interest in negotiating with him. Her attractive head was tilted to the side as she studied the lieutenant in more detail.

"What about you, Peter?" She asked. "You don't smell like the others. You say that you know what humans smell like, but you don't share their scent?"

A line appeared down the side of Peter's face as his jaw clenched.

"Don't change the subject." He said. "Where's Jane Wilson?"

"You'll get her back when you tell me what you are."

"So she is alive?"

Karina said nothing and merely smiled at him. But she wasn't going to say another word until she got her answer, and Peter had already proven equally tight-lipped when it came to discussing anything to do with what he was.

They were not going to get anywhere, Rose realised.

"We're sorry about your family." She told Karina. "But if Jane is still alive, then we just want her back."

Any remaining shred of hope that the alien was capable of showing any form of empathy disappeared the moment Karina laid eyes on her. It was as though she was lining Rose up to be her next meal. Did she want to take her form, or was it simply that she just wanted to make a kill?

"You think I care about those weakling boys?" She hissed. "If they got themselves killed trying to get the best forms and showing off to one another then they have only themselves to blame. Their parents went the same way and I ended up getting stuck with them."

Despite the disgust Rose felt, she could in some small way understand where Karina was coming from.

How many times had the Doctor landed them both in trouble because he simply hadn't shut up? She could also recall one particular trip to A&E with Mickey after a failed attempt to impress her with a skateboard back when they'd been kids. But then she thought back to the baby creature that had almost killed Stefan. Did Karina not care at all about the infant at the very least? Perhaps she didn't realise that it was dead too, blasted away by Peter's shotgun.

The question came out before she could stop herself.

"Why? Why don't you care about them?" She asked. "There was a baby and -"

"Oh, my dear girl." Karina laughed. "Our kind can quite easily fend for themselves from the moment that we're born."

"Mother of the year, aren't you?" Peter quipped. "Don't tell me that you hold no value on anyone's life but your own?"

"Come now, Peter. You're making me sound so heartless."

"If I couldn't hear it then I would say you didn't have one." He rebuked. "So you wouldn't mind if I just went ahead and put a bullet in the back of Karugon's head?"

Karina's smile vanished as her eyes flickered over to her nephew.

"You'd be willing to execute him?" She questioned. "He looks just like you. Wouldn't it be like shooting yourself?"

"You think that bothers me?" Peter stated cooly. "Where is Jane Wilson?"

He didn't want to delay finding her. If Karina was a mirror image of Jane then she wasn't going to be in the best shape. Certainly, she would be dehydrated and exhausted at the very least and could have already quite easily died of exposure long before the creatures got round to killing her.

Also, he could sense that Karina was formulating a plan. She was scheming her way out of here, he was sure of it.

"She's in the ship." The alien admitted. "Alive, just about."

Despite gaining the information he'd wanted, Peter made no effort to move towards the spaceship. Karina manic smile returned as she plucked the very thought from his head. "Not very trusting, are you?" She giggled. "I suppose you want to know what I want in return?"

"Isn't the safe return of your nephew good enough?"

"No, it isn't. Because, as I've made it perfectly clear to you, he can look after himself."

"So what do you want?" The Doctor asked. "A long life, I suppose?"

A frown had appeared on the Time Lord's brow as he also sensed the looming danger.

"You think I want your ancient body, old man?" Karina ground back. "That is a male ambition amongst our kind. To acquire the longest life span available."

"Worked out for them well, didn't it?" Peter pointed out. "What do you want then, if not age?"

Slowly, almost to the point of seduction, Karina closed the gap between them. She hesitated when she saw the hand he was holding the gun with twitch in anticipation, but she continued when Peter did not raise the weapon any further.

Stood close enough to the lieutenant that she could now reach up and stroke his face if she wanted to, it was clear that she was enjoying all of the attention she was receiving. Rose could see how happy it was making the alien to have all of these men available to string along with her games.

It was making her angry.

"Beauty is only skin deep." Karina declared. "There's no point in living forever when you look hideous."

"That's it?" Peter scoffed with disbelief. "You want to look pretty?"

"Am I not in this body?" She replied. "In truth, I know she's in a bit of a state. Maybe a new form is in order?"

Rose flinched as Karina looked her way. There was no mistaking her intentions now.

"You leave her alone." The Doctor warned. "Karina, I am going -"

"Oh, I'm not done yet, Time Lord." She cut in. "I want one more thing first."

She turned back to face Peter. He was still only stood a few inches away from her, and his irritation was plain to see.

"What?" He growled. "What do you want?"

But he already knew what she was about to ask of him. It was the same question that had been floating around the entire night, one that even the Doctor and Rose wanted to hear the answer too. Already, a spark of fear had ignited within, and Peter knew that he couldn't avoid answering if it meant that Jane Wilson's life hung in the balance. He had to admit the truth and tell her what he was…

The only problem with that was that he didn't know. He'd never known.

"I'm waiting, Peter." Karina huffed impatiently. "Tell me what's hiding under that human face of yours?"

"I don't…"

Peter was surprised when Karina caught hold of his arm as she decided to explain herself. The alien's tone was almost kind and gentle and it did not suit her in the least. But she wanted a response from him, and she was determined to get it.

"You and I are kindred spirits." She told him. "These weak little humans and dusty old Time Lords are nothing compared to you and me. We hunt and kill without fear because nothing and no one else can compete with what we are. Bloodshed is our second nature, isn't it?"

It was enough to rattle anyone's resolve. Karina had spoken with such passion and excitement that it was obvious that stealing lives was not simply a method of survival to her. She enjoyed it and found the whole morbid business fun. Now she was forcing Peter into doing something he'd probably spent his whole life avoiding. Worst still, she was bargaining with an innocent person's life to get what she wanted.

Rose's no longer felt afraid of the alien. Now that Karina looked human it only made her look less intimidating and more like a crazed woman with nothing but vile words on her side.

"How dare you!?" She shouted at her. "Your whole family is dead and all you care about is messing around with us. Well, we're done playing, Karina. So give us back Jane Wilson."

It did not have the effect she desired.

As the last echoes of her voice faded away, Rose could see that Karina's amusement had not wavered. But it was as the Doctor turned her way with fear in his eyes that she realised the gravity of the mistake she'd made.

Karina already wanted her. Rose had simply just served up a very loud reminder of that.

"Well, aren't you a feisty one?" The alien purred. "So young, so pretty."

"You leave her alone." The Doctor growled. "Karina, whatever -"

"Oh, enough!" She moaned. "You're spoiling my fun."

Her gleaming eyes jumped to Peter. She was ready to hear his answer to her demands. But the steely, unwavering gaze she was met with told her what he was going to say and it was enough to make her sly smile falter.

"The only thing I am going to offer you is your life." He informed her. "Surrender now or I put you both down. Starting with your nephew."

"Karina!" Karugon whimpered. "Please don't let him -"

"But quiet, boy!" She hissed. "I will handle this."

The balance had suddenly shifted. She was no longer as confident or as detached as she had been before. Now that Karugon's life was in her hands and she faced the prospect of losing her own, she was far more reluctant to stand by and allow it to happen.

"You'll handle nothing," Peter told her. "Except your surrender."

Karina nodded with some reluctance.

"Yes, I suppose you win." She admitted. "You must be very strong to have taken down Kalagan and his other brothers. Very strong indeed. I wonder how strong, though? Could you break say… the bindings around your wrists?"

The glance she exchanged with Karugon warned Peter of the danger a split second before the meaning of her words registered with him. Instantly, he knew what was about to happen and cursed himself for not thinking about it earlier.

But it was too late.

There was a loud clink from the other side of the cave as Karugon broke apart the metal handcuffs that were binding his hands as if they had been made from plastic. He might have learned he was able to do it from watching Peter break the shackle on the table, or maybe he had felt some of the inherited strength coursing through his new muscles. It didn't matter now, Karina had given her orders and had chosen her moment perfectly.

What Karugon did next brought control of the situation back to himself and his aunt.

Thinking that the alien was simply trying to run away, Stefan had tried to stop him. But the alien had no intentions of going anywhere and was quicker than he was. Striking the corporal across the face, he grabbed him by the throat and wrapped his arm around his neck so that he could snap it just as easily as he'd broken Peter's leg.

"No!" Peter shouted, turning around. "Let him - "

A huge black mass of leathery muscle seized hold of him. Long claws were threatening his jugular but it was the tightening squeeze being applied against his windpipe that cut him off, forcing him to his knees as he was slowly and painfully being choked to death.

Karina's limb was no longer a human arm. It alone had transformed the moment Peter had turned his back on her.

"Oh, lieutenant." She chuckled. "Don't say that I didn't give you a fair chance. You should know to never turn your back on someone like me."

The Doctor had the sonic screwdriver in his hand. But both soldiers had dropped their guns when they had been captured and they were in such perilous danger that there was very little he could do. One wrong move and one or both men would be killed on the spot.

"Let them go!" Rose cried. "Please, don't do this."

Karina found her pleading very funny.

"Give me your blood and I'll think about it." She proposed. "Just a little sip, that's all I need."

Rose hesitated, but it was only for a second.

Peter's face was turning red and his eyes were beginning to roll. He was losing oxygen fast and Karina only had to tense her fist a little more before his neck broke. Behind her, Stefan was being held firmly in place by Karugon. The Doctor's inaction had already told her that he too was powerless to act. It was all up to her.

There was no denying the alien's hungry looks now, and she knew the consequences of her refusal.

"Okay, just let them go first." She begged. "I'll give you what you want."

"Rose…" The Doctor began. "She won't just take one drop."

"Hush now," Karina told him, eyeing Rose greedily. "She's doing the sensible thing."

Rose felt her foot take a step forward before the other reluctantly followed. She found herself walking towards what she hoped wouldn't be her own death.

"Rose… not another…" Peter tried to say. "Stay…"

Even now he was ordering her around.

Rose knew she couldn't obey him this time, even if she wanted to. If Peter and Stefan were killed she knew that herself and the Doctor, along with Jane Wilson, would not stand a chance in getting out of these caves alive. There was still the possibility, however, of them all living as long as Karina thought that she was going to get what she wanted.

But that gave Rose an idea. Well… it was more of a hope.

"Let them go first." She ordered. "You can have me, but let them go first."

Karina knew that she didn't have to compromise with her, but perhaps she sensed the difficulty of feeding on Rose whilst holding onto Peter as he continued to fight against her grip. He was getting weaker by the second but she still couldn't risk relaxing her arm just yet.

"Oh, very well." She agreed. "But just this one until I am done with you."

With a single throw of her arm, she tossed Peter aside like a discarded doll.

He landed hard and rolled over several times, his arms and face scraping badly against the rocky ground. Coming to rest on his stomach, he was coughing horribly and did not make any effort to get himself back up onto his feet.

Laughing at his pain, Karina stared down at him with an unimpressed look.

"How sad it is." She told him. "You are unwilling to embrace your true nature and are afraid of it. Even at the cost of defending your pack."

Peter didn't respond. He could barely breathe, let alone do anything to stop her. Utterly defeated, he didn't look up to meet with her cruel gaze.

Turning away from the lieutenant, Karina smiled again as she returned her attention to Rose and took a step towards her. Free of her captive, there was now nothing and no one left that she considered capable of preventing her from taking her new form.

She frowned when the Doctor stepped in-between her and Rose.

"Now that it is far enough." He told her sternly. "This is your last warning, Karina."

He still had the sonic screwdriver in his hand.

"What is that?" Karina questioned, spotting it. "That thing in your hand?"

"It's a screwdriver."

"So, it's not a weapon?"

"No." He said. "But it is very good at giving people headaches."

Peter's head shot up as his eyes widened with the realisation of what was about to happen. Even before the Doctor had raised the small metal tube up into the air, the lieutenant had already clamped his hands firmly over his ears.

This time Rose heard the noise that erupted out of the sonic screwdriver.

It sounded like a blaring alarm clock that did not have a snooze button. Horrendously loud, she felt as though her eardrums were going to burst. But then Rose saw that this was nothing compared to what it was doing to Peter and the two creatures.

The lieutenant's face had turned red again and was contorted with pain. Curled up in a ball on the ground, he was keeping his hands held firmly over his ears as he tried to block out the invading attack on his super-sensitive hearing. Karina had fallen to her knees, her one human arm and monstrous limb both protecting her skull against the audible attack.

But it was Karugon that had been the Doctor's real target. The alien had immediately let go of Stefan as he had stubbled away as though trying to somehow run from the terrible noise. He didn't even see the sucker-punch blow Stefan lashed out with as it struck him square in the jaw.

The alien was out cold long before he hit the ground.

Satisfied with the result, the Doctor lowered the sonic screwdriver and the noise stopped almost at once. There were only a few echoing remnants that lingered almost as long as it took Karina to come around to understanding what had just happened.

"What have you done!?" She shrieked, wincing as she stood back up. "Karugon, get up!"

"Oh, he won't be up for a while. Not after a punch like that." The Doctor replied, smiling in Stefan's direction. "Nice left hook, corporal."

The Time Lord barged past Karina without so much of a passing glance. The creature was too stunned to do anything, and right now she was the least of his concerns as he made his way over to Peter.

The lieutenant had managed to sit himself up and had taken his hands away from his ears. Droplets of blood had dribbled out, leaving small red trails running down his neck. The marks on his face and arms were already almost gone, as was the large ring of bruises around his neck. But it was the ringing noise still pulsating through his eardrums that was causing him the most discomfort.

"Ouch.." He remarked. "My head…"

Reaching him, the Doctor held out his hand.

"Come on, soldier. On your feet."

Peter didn't hesitate in taking it. Rather unsteadily regaining his feet, he nodded gratefully to the Time Lord.

"Thank you." He told him. "I should have… I didn't…"

He tailed off, shaking his head at his own mistakes.

"You have done more than most people ever could." The Doctor told him kindly, resting a hand on his shoulder. "No one would blame you for calling it a day."

Frowning as he looked back at him, Peter opened his mouth to argue. No, he was not finished yet, not whilst Karina and her twisted plans still threatened them all, and certainly not until Jane Wilson was rescued.

"What the hell are you talking about?" He asked him. "This isn't the time to be smiling, Doctor!"

The Doctor was grinning in the most peculiar and slightly smug way.

"No, but it is time for you to stop hiding how brilliant you are." He countered. "Peter Alexander Argent, you've come all this way with more than one hand tied behind your back and that ends right now."

"Doctor, I can't -"

"I know you have your reasons." The Doctor interrupted. "But right now we need it. We need you, Peter. Karina has had enough chances."

At the sound of her name being mentioned, the alien regained some of her crazed conviction that no one was capable of stopping her. Despite being outnumbered four to one, she cackled loudly as she turned to face the Doctor and Peter.

"What?" She giggled. "You think he's going to save you all? He is just a pathetic mutt who's afraid of his own shadow."

She was completely unhinged now. There was not a shred of humanity left and her human disguise was fading with every passing moment. Black leathery skin was slowly spreading over the pale pink as her face slowly started to stretch out wide, her chin almost on the verge of becoming a snout.

Something about this final insult triggered something within Peter.

It wasn't so much as a conscious decision, he was still so scared of taking that final step and giving away his secret. But then Karina turned her back on him and started to advance towards Rose and he knew that there was no more holding it in.

At the last possible moment, he issued his final ultimatum

"Do not turn your back on me, Karina!" He bellowed. "Take one more step and you are finished!"

Karina ignored him and did not turn around or stop. As a result, she did not see his eyes explode with yellow light...

At first, Rose didn't spot this either. All she could focus on was the nightmarish, still half-human looking monstrous creature stalking towards her. Jane Wilson's pretty face marred with fangs and bulging black eyes devoid of any conscious soul would have given her nightmares for years to come had she not been expecting to be torn apart any second.

Then she heard a snarling growl that did not belong to Karina.

The alien stopped curiously at the rumbling echo and watched as Rose's gaze drifted towards what had made such a sound. Seeing the human girl's mouth open wide with amazement rather than the fear that should have been expected, Karina finally turned back around to where the Doctor and Peter had been stood.

But Peter was no longer there. He had simply vanished, and what had taken his place was truly a magnificent sight to behold.

It was a wolf. An enormous wolf.