She walked through the empty corridors to the Prime Minister's office, where she saw him sitting at a table with dead people all around him. He pointed his gun at her.

She was scared now. She had fended for herself in that hostile environment, and now a man she had put all her trust in was prepared to kill her. For what? To keep his reputation? It certainly wouldn't do either of them any good. "Look, I'm here to help you. Put the gun down and we can talk about this."

He thought about it for a minute, but then put the gun down and beckoned for her to sit at the table. She sat opposite him, sandwiched in between two dead MPs. She looked into their cold, dead eyes and looked back at him. "Why did you have to do this?"

"They had contracted the virus. I had to do something to prevent myself contracting it. They had to die." She understood, but she wondered how he could be like this, so calm. She fell to pieces, and yet he, the man who cared for the welfare of the country felt like a machine. Something wasn't right, and she could feel it. Under the table she tightened the grip on her gun.

"What are we going to do about this invasion?"

"Nothing. There is nothing we can do. They have got us right where they want us."

"I beg to differ."

"Miss Klein, I am doing nothing about this situation." He was remorseless. She knew something was wrong.

"I voted for you because I believed in what you could do for this country. Wait... how did you know my name?"

"You told me."

"I told you my first name. Not my surname." She saw a sudden movement from him, but she was quicker, pulling out her gun and shooting him several times. She realised he was the sleeper agent Anneka was talking about.

The emergency phone began to ring. Lilly answered it. "Hello"

"Where's the prime minster?"

"Your guess is as good as mine."

"This is UNIT Brigadier King, we need to speak to whoever is in charge."

"I guess that would be me then." She was now the only one in a position of power.

"They've taken most of our forces. We have nothing to defend ourselves with. Who are you exactly?"

"Torchwood. And I'm going to stop this, with or without any help."

He hung up on her, and she stood up preparing for what to do next, when she appeared in the doorway. Then all the pieces slotted into place. The Prime Minister was a doppelganger, and so was this creature. The doppelganger rushed at her, knocking her on to the table. She dropped her gun on the floor, and the doppelganger grabbed it. The two women grappled, with Lilly gaining the upper hand over her doppelganger, knocking her over.

She reached around for her rifle, but the doppelganger was heading for the window. Lilly shot her in the hand, and she dropped the gun to the floor. She reloaded, aiming for her again, but the doppelganger was now on an opposite roof. She fired at her, hitting her square in the stomach. The doppelganger fell backwards, and Lilly had no way of knowing whether she had died or not.

She knew that the only way to clone someone was to get a sample, and that's exactly what Sylvester had done to her. That would mean that one of the agents Torchwood sent to her was a sleeper agent. And they would be in big trouble when Lilly got to them. She got a message on her phone from Anneka telling her that the alien she killed earlier was a biological creation made with gene splicing. She guessed that the invaders were a race of scientists because of their work with gene splicing and cloning, but she didn't know what they needed the human race for.

First she realised that she needed to find out who was the sleeper. She made a call to HQ.

"Hello, HQ, it's Agent Klein."

"Lilly, we're in dire straits. They have taken several of our agents."

"Look, there's something I need to ask you. It's about the agents you sent me..."

"You mean agent."

"No, I got two agents. Anneka and Sylvester."

"I only sent Anneka from the North branch. Where was Sylvester from?"

"He said he came from HQ. He's Rupert's brother."

"Lilly... Rupert didn't have a brother. He was an only child."