"Inside her head. They're so alone."
— Lady Cassandra O'Brien, New Earth

Penelope felt like she was floating. Not the nice kind of floating, like being let loose on a floaty for the first time at a pool, but finding yourself stranded in the ocean and knowing that only floating saves you from the murky depths.

She could hear her voice and feel the pull of her limbs moving, but couldn't recall making those movements. Opening her eyes, she was horrified to suddenly feel like an outsider in her own body.

Doctor? What's going on?

Her figure scoffed, flicking back the ginger hair as the real Penelope tried to move against the heaviness around her.

"It's nothing to worry about honey. Your precious Doctor and.. the blonde one are okay. Just waking them to wake up."

Who are you? Why are you doing this?

The woman with Penelope's face scoffed, the real girl not liking that expression on her features.

"I am Lady Cassandra, and I am the last human. Not your pathetic Rose, who, I will have you know, tried to kill me with your Doctor when we last met. You weren't there, unfortunately, would've loved to meet you in person." A confused expression flitted across the reflection, a true representation of how Penelope felt.

I'm sorry Cassandra, but you can't do this. I-

There was a sudden sharp pain in her head, causing her to stop talking. The heavy feeling constricted her throat and threatened to close it.

A continued confused expression stayed a little longer than Cassandra would like to admit, but she had to drop that when the Doctor and Rose Tyler started to wake up in the cell before her.

The ginger girl kept quiet throughout, only making small protests here and there that Cassandra ignored. It wasn't until the Doctor offered himself to take the pressure off her brain that she made a proper stand.

NO!

Cassandra cowered back at the loudness reverberating around her borrowed mind. She smiled nervously to both of the people watching her, knowing there was no way to explain that.

"Well, she didn't like that idea all too much." The Doctor looked concerned, a touch of pride swirling behind his eyes. Behind Cassandra, Penelope argued into the abyss.

He is far more important than I am right now. I'm not going to fix this am I? Say that I said rather me than him.

"Oh do I have to." The small temper tantrum did nothing to dispel Penelope's ranting.

Cassandra!

"Oh alright, goodness you're so bossy." The body thief repeated the statement, defending herself when the Doctor argued. Penelope also continued to shout from inside her own head, eventually Cassandra must've had enough as she moved to the Doctor.

Suddenly being given control of herself again was not as pleasant as she hoped, by which, Penelope Adaams fell ungracefully to the floor. Rose was immediately by her side, helping her up, knowing the Doctor could handle himself.

"Penelope?"

"I-I'm okay. What's going on? I don't remember much." Rose looked guilty at her, both of them choosing to ignore Cassandra getting used to her new body.

"Well you - Cassandra - opened all the cells and the people kill anyone that they touch. We stopped so the Doctor could help you." Penelope was slouched over a bar, taking it in. She was quiet, eyes pricked with tears.

"I did this?" Rose panicked a little, not expecting her to take it that way. Although it wasn't like she could guess correctly, she barely knows this woman.

"No! No. God no, of course not. This was Cassandra, I know what it's like in her head, you couldn't have done anything. This is not your fault, everyone knows that, the Doctor knows that." She nods, not quite accepting that, but knowing there was a more profound matter they need to take care of. Although she didn't get long to grieve her mistakes before the Doctor's face popped up between them.

"Hate to break up your little gossip, but they're getting in." As if they heard her words, the door flew open as she started to panic. "What do we do? What would he do? The Doctor, what the hell would he do?" Penelope looked around as quick as the fog on her mind would allowed.

"Ladder. Get up the ladder." Cassandra pushed past them both to get to the ladder first, the two sharing a look before following after. Rose made sure that Penelope went up before her, knowing that Cassandra had more of an effect on her.

Before they knew it, they were at the top of the ladder, only having had one incident in which one of the nurses fell. Penelope didn't have time to worry about them, knowing there was nothing that could've been done. Now, though, they were arguing about Cassandra being in the Doctor again. Penelope was glaring at the figure of the Doctor.

"Cassandra just go back into me again, we need the Doctor." His eyes rolled sarcastically.

"Of course, you would offer. Your Doctor won't be too happy with me."

"I don't care, he can deal with you after. But there isn't going to be an after if you don't get a move on."

"Oh all right." There was sudden darkness in which Penelope was floating in her head again. The Doctor was already looking down at her.

Don't let him argue, I'm not changing my mind.

"Sorry Doctor, your Penelope isn't letting you argue. She says that she isn't changing her mind. So will you please just open the door."

"Not till you get out of her." Penelope continued to threaten Cassandra, knowing the tightness was returning.

"She really isn't giving in. And she's right, we need the Doctor."

"And I need her. I order you to leave." If Penelope had control of her ears they would be burning, but she could vaguely feel Cassandra blushing lightly using her face.

After a little more back and forth, Cassandra goes into one of the afflicted patients climbing behind them. For the first time in a while, Penelope was able to smile up at the Doctor and have him smile back.

He opened the door and jumped through, quickly helping both girls through, trying to beat Cassandra. But Penelope felt like she was hit from behind, sprawling out on the floor before the other two people. The Doctor was immediately at Cassandra again to give her back, failing to notice the expression on his friend's face.

"That was your last warning, Cassandra." Even Penelope could feel the emptiness that the woman controlling her body had felt. It was something that crept up on you and convinced you that you were alone, it's horrible.

"Inside her head. They're so alone. They keep reaching out just to hold us. All their lives, and they've never been touched." Penelope felt tears stream down her face, unable to imagine the thought of being alone for that long.

The Doctor held out his hand and Cassandra took it, making matters worse when Penelope realised she missed being actually able to hold his hand. And then he was surprised at how alone he felt when Cassandra immediately removed her hand from his. Holding onto Penelope had become natural, even in the short time they had, and they both knew it.

He unlocks a door as banging continues behind them, opening and revealing the Face of Boe. The woman from earlier charged at them, holding the business end of a chair towards them.