A/N: Okay, I'm not that cruel. I won't leave you hanging. But be warned this chapter won't answer all your questions and I still haven't finished. But hopefully it'll allow you to make more sense of why the Doctor regenerated and what happened to Cassandra. And thank you to PotterheadWhovian7 for pointing out what they did. :)

But enjoy chapter eight. Please enjoy chapter eight. xD I promise I'll answer any questions you post in reviews and try to fix them up asap. I'd appreciate it so much. :)

Jack once again wrapped his arms around the would-be-doctor, mentally assuring himself it would be alright in the end. The Doctor is always alright. The Doctor always makes it through.

Cassandra then whimpered again, and Jack could only shield his eyes as the Doctor's body erupted into a mass of yellow and orange flames.

Jack wondered to himself – Cassandra had said the serum would stop the Doctor regenerating. Obviously she had been wrong, since right now he was doing exactly that. Or maybe the mist was clearing and wearing off, since the room was considerably lighter, although that was probably the residual energy from the Doctor.

And then the light stopped, and they were plunged into darkness once again.

"Doctor?" Martha immediately cried, rushing to where she last saw the TARDIS.

Jack tried to keep hold of her, in case she tripped and fell, but she was gone before he could grasp her arm and pull her back.

"M-Martha?" A weak voice wallowed its way through the darkness, and Jack recognized it as the Doctor's.

Did he change? He sounded the same.

"Where are you? Are you okay?"

"M-my head…"

Yes, that was almost certainly the Doctor's tenth incarnation and his voice. Jack was puzzled – the man had regenerated against all of odds – and apparently voluntarily – but still he had managed to keep his tenth voice. Maybe he'd finally learned to gain control and remained the same?

The doors opened to the TARDIS to reveal Martha crouching by the Doctor. Jack discovered to his amazement the Doctor still looked exactly the same. So what happened?

"Gwen, can I have the handcuff key?" Martha asked, and Gwen stepped forward to remove the ring from around the Doctor's wrist.

"It might still be her." Owen said dryly. "She might be acting."

The Doctor then mumbled something that was clearly not English very quietly, to confirm he was actually the Doctor and Cassandra was gone.

"Maybe not." Owen shrunk back, embarrassed.

Martha and Gwen soon had the Doctor supported and were walking him into the TARDIS. Torchwood Three followed. The mist around them was no longer flowing into the TARDIS, which was a good sign. As soon as Jack was inside, the doors slammed shut and the dematerialization noise echoed around the console room.

Minutes earlier …

Cassandra, you don't have to see any more. It pains me as much as it pains you, and the longer you're here the stronger it gets… It's a defence mechanism. It's normal and you're suffering because of it.

H-how do I stop it?

Regenerate.

What?

Regenerate. Allow my body to build up with residual energy so it will push you out.

B-but you can't… The serum stops energy build up.

You'd be surprised how much residual energy I can build up, and I can tell you, a stupid gas that stops wounds from closing up won't get you very far. It may stop immediate regeneration, so I'm dead for a couple of minutes, but then the build-up will become so strong that it just has to happen, or my body will burn from the inside out.

It's impossible, Doctor… Y-you won't be able to regenerate here. The serum s-stops it. Please believe me.

The TARDIS will help us. She's inside your head, and she's not very happy. She wants you out. So she'll help us build up lots of residual energy to trigger a voluntary regeneration.

But you can't…

Watch me, Cassandra. If it doesn't work then I guess we're stuck like this. And neither the TARDIS nor myself appreciates being tucked away to one side in our own mind.

O-okay. What do I do?

First of all, stop blubbering out my life story. And then just focus on dying. Tell yourself you want to die. You want to die right this very moment.

Won't you die too?

Only you. You're in control of me. I'm separated from my body and part of my mind now, so once you're gone I can come back.

I'm going to die if I do this?

I can see inside your head too, Cassandra. We're both old and tired. We both just want to die so we can stop all the suffering. You've been alive past your time and you've seen more than you want to see. I want to save you, but you don't want to be saved and I can see it.

Will it hurt?

If you do it properly, it won't hurt.

Won't you change your face? The first time I met you, you had barely any hair. And now you're younger and have lots of hair.

Don't worry about that. I'll control it.

But you said you're separated.

Once you start it, I can finish it. Once it's started you'll start to get pushed out, and I can start to seep back in and take control again.

I feel w-warm…

So I heard. Jack knows what's going on. I'm sorry it came to this Cassandra, I'm so sorry. You don't deserve to be burdened with my memories.

Doctor.

Yes Cassandra?

I think you're amazing.

Thank you?

You can live with all this pain and guilt. I had to go and make you suffer to live with mine. You've never hurt anyone before. How do you do it?

You're almost there, Cassandra, I can feel my fingers now…

Doctor.

I don't do it. You've been wondering why I like humans so much. Humans are so loving and they remind me you don't always have to worry about what's bothering you. It's easier just to smile and get on with your life. You told everyone that yourself, so you should know.

I'm sorry…

Don't be sorry. I'm not angry at you. It was wrong to leave you for dead on Platform One and I've paid the price for it. We're even.

Yes… Even…

I don't want you to die thinking I hate you.

You have every right to hate me…

But I don't.

I'll never understand you… It's getting so dark.

You're almost there. Just a few more seconds and it'll be all over. I can see now. I can see and once you're gone I can stop before I change.

You're a remarkable man, Doctor. I don't understand how you beat the serum or how you can let your torture go so easily.

… Goodbye, Cassandra.

Goodbye Doctor.

And then to the Doctor's demesne, it was dark again. He blinked several times and then ran his free hand through his hair. To his relief it was still spiky, which meant he hadn't regenerated just yet. His teeth felt the same and his body ached from the residual energy.

"Doctor?" He recognized it as Martha's voice, and he could hear her stumbling in the dark to find him.

"M-Martha?" He discovered he had his voice back.

"Where are you? Are you okay?" Typical Martha – the residual energy will help his injuries to heal up faster so he'll be fine.

"M-my head…" He groaned, realizing the forced psychological entry and forced regeneration had given him a massive headache.

The headache wasn't like before, when Cassandra was growing inside his head. This headache confirmed the Last Human was gone and had been plainly ripped out of his head by the excess residual energy the TARDIS and he had built up.

Open the doors so she can find us, old girl. It's dark out here.

I'm so glad to hear your voice again, Theta.

"Gwen, can I have the handcuff key?" Martha had finally spotted her shattered Timelord.

Oh, yes, that's right. He was handcuffed to the TARDIS. Jack always had wonderful ideas. Gwen then eased the ring off his wrist and it fell to his side. Blood rushed to the offended wrist. He hadn't noticed it was numb from lack of circulation.

"It might still be her." The Doctor heard Torchwood's medic mutter. "She might be acting."

The Doctor took this moment to mumble, "After almost killing myself, you humans still doubt me." in Gallifreyan quietly.

"Maybe not." Owen shrunk back, obviously embarrassed by his mistake.

The Doctor soon had two arms around Martha and Gwen's shoulders and he was safely inside the TARDIS. Some of the serum had gotten in, but she'd obviously gone and turned on the ventilation fans to clear the console room.

I'm going to take you home, Theta.

Where is home?

I'm sure you have a pretty good idea where home is by now.

The TARDIS dematerialized and the Doctor had a pretty good idea where they were going. The TARDIS eventually shuddered to a stop and the Doctor staggered to his feet, much to Martha and Owen's protests. The TARDIS didn't object. She nudged him along as he laid his hand on the door handle.

The Doctor pulled open the door and immediately his lips curled into a smile. He looked back at Martha and Torchwood Three, still smiling. They all returned it and they came down to see where they were.

I don't know where I'd be without you, dear.

Because of course, the Doctor was looking over Earth from space. Earth was his home. Gallifrey was gone and now Earth was the second-best place.

"You should all grab some sleep." He announced to Torchwood Three. "The TARDIS seems to like all of you so she'll show you where you can sleep."

They all dispatched, glad of the offer the Doctor had made them. Apart from Martha. Martha slipped her hand into the Doctor's and squeezed it tightly as they looked over Earth.

"And you, mister, are going to be sleeping where I can see you tonight." She said firmly.

"I'll be fine, Martha." He reassured her.

"We both know that's a lie." Martha smiled. "You're coming to the med-bay with me and I'm going to run some tests." She tugged him back towards the console, and then down one of the corridors the TARDIS indicated.

"You have to sleep too." The Doctor objected as he was pulled along.

"I'm almost a doctor." Martha retorted. "Being tired is nothing new." She reminded him with a smile as she turned into the med-bay.

Martha gathered some equipment she identified as human when she entered, leaving the Doctor to lie down on the bed. She knew he wasn't okay. He still had a long way to go before he was the Doctor again.

"Now…" She started, deciding to pick up the stethoscope first. "Are we experiencing any pain, Mr Smith?" She turned to him, glad to be mentioning the old joke, but she found he was asleep.

She set the stethoscope down reluctantly, still feeling concerned about him as he lay there completely still. She brushed his fringe back with her fingers gently as she looked over his sleeping form.

"I think you deserve this one." She told him.

She was aware he only slept in the Torchwood Hub because his body had forced him into a healing coma. She'd done a little bit of reading when he was missing, but nothing more. This was the first actual sleep he'd had since he was rescued. Martha was sure he'd been running on adrenaline these past few hours and when he woke up they'd be back on square one. But she could live with that.

"Patient troubles?" Jack had appeared in the doorway, smiling at her and the Doctor with his arms crossed.

"He deserves some rest." Martha said.

"He deserves to rest more than any of us." Jack stated. "He wasn't ready to do what he did today, and I'm surprised he's still in one piece." He smiled slightly. "You better be ready to take care of him, Martha Jones."

"I'm more than prepared." Martha told him. "And what happens now? The Hub is full of deadly serum." She remembered.

"Nothing a couple of ventilation fans can't take care of." Jack flipped open his vortex manipulator and pressed a couple of buttons. "We can head back tomorrow morning." He said with a smile.

"I still don't understand how he regenerated and didn't change." Martha uttered, finding herself in the doorway too, watching the Doctor sleep.

"He'll be able to answer that himself, I hope." Jack didn't have any answers either. "Just give him time." Jack turned to Martha and held his arms out, obviously showing he wanted a hug.

Martha smiled at his offer and took up the offer. Jack hugged her tightly, but not as tenderly as he did in the Hub before.

"Goodnight, Martha Jones." Jack said in her ear.

"See you in the morning, Captain Jack Harkness." Martha responded in the same fashion and then Jack was gone, walking down the hallway towards where the TARDIS had chosen his room.

Martha still had plenty of questions. She wanted to know how he had regenerated in the mist, and where Cassandra had gone. She wanted to know who Adam Mitchell and Cassandra had been and what they meant to the Doctor. Most of all, she wanted to know if what Cassandra had told her was true. Did the Doctor know she admired him?

"I love you, Doctor." Martha whispered, before flicking out the lights and collapsing on the closest chair.

PS. Hey! You made it to the end! There was a sequel for this but I deleted it after much debate with myself - the writing was bad and I wasn't happening with the turn the piece had taken or the way I decided to write it when I was posting. If you want to read it hit me up a PM and I'll see to sending it to you through the document exchange. Thanks! :)