It was eerily quiet, with just the sound of everyone's feet shuffling down the rungs of the ladder. The Doctor hit the bottom and in front of him was a small service-tunnel, scantily-lit by a few lamps and lanterns. As everyone gathered at the bottom of the shaft, the masked men led the way, with the Doctor and Amy walking in the middle as if they were being led in a convoy. The tunnel stretched out for what seemed a mile, but they eventually arrived at a dead-end. However, one of the men pulled away a panel on the wall, touched two wires together and the wall in front of them slid away in a much delayed manner. Behind the bulkhead, they were met by a dim light and they were brought into the room, before the wall slammed shut behind them. The room they were standing in was the size of a hall, and had many people slumming on the floor, with moth-eaten blankets covering their shaking bodies and legs. The atmosphere was grim; everyone in the room looked pale and tired, staring at the Doctor and Amy with bleak expressions. As this point, the masked men were no longer masked; they had taken off their gas-masks and dropped them onto the thin, metal surface, revealing the same bleak expressions that everyone else in the room was wearing on their faces. One of the men, who had ruffled brown hair that pointed out wildly, clicked his fingers in the Doctor's face, who was taking in his surroundings.

"You, Doctor, follow the man with the bald head. He will take you to see the captain."

The Doctor nodded in confirmation, as he went to join the aforementioned man, who took him to the back of the room, where an older gentleman was crouched in the corner. His area of the room was slightly brighter than everyone else, illuminated by several torches on the floor. He was crouching over a large piece of paper, which the Doctor deduced was a map, a blueprint of some kind.

"Captain?"

The gentlemen did not break his concentration to talk to the man, who was waiting with the Doctor and Amy. Instead, he just spoke without looking at him.

"Yes, 53?"

"We recovered two survivors on the surface; one of them is a doctor."

The captain then broke his focus, turning away from his work to look up at the Doctor, who was standing idly, blinking wildly at the intense torch light in that section of the room.

"Really? A doctor?"

The captain stood on his feet, towering over the Doctor in terms of height and firmly grabbed his hand and shook it almost off his wrist.

"53, leave me with the Doctor and make sure everyone is properly hydrated."

The abstractly-named 53 followed the captain's orders and left the Doctor and Amy with his superior.

"It's good to meet you, Doctor…?"

The captain waited, as if he was waiting for the Doctor to fill in the rest of his name.

"Oh, no second name, just the Doctor will do fine."

"Fine by me, who is the female to your side?"

Amy took it upon herself to introduce herself to the captain.

"I'm Amelia Pond. Or Amy, whatever is good for you."

Then the Doctor interrupted the introductions with a serious, business-like persona.

"Great, now that we are introduced, I would like to know exactly what is happening here, because I was sort-of forced to come here at gunpoint, so you must really need me."

"I apologise for that, but it's probably best that you came down here."

"Why? Why are you here? And where is everyone on the surface?"

The captain sighed, before crouching back onto the floor, motioning for the Doctor and Amy to do the same. He then spoke in a hushed voice, almost a whisper, trying not to alert the people around him.

"I led a group of soldiers here, at the instruction of the Shadow Proclamation, after Xena was put on lockdown."

"Lockdown?"

"Yes, the universal economy crashed and we heard nothing from the planet. People got worried and we were sent to find out what had happened."

"How long ago was that?"

"We arrived a week ago, with the objective of finding out what happened and reporting back to the Proclamation, but our communicators don't work, so we were stranded. We found this place on arrival, set up base and tried to access the video archives to find out why Xena went into lockdown. We also started trying to find people on the surface, which we did. The survivors have helped us to piece together what happened."

"So, what did happen?"

The captain tapped his fingers on the floor, before getting back to his feet and telling the Doctor to follow him. They walked across the room and to the opposite corner, where there was a small monitor embedded in the wall. Using the touch screen interface, the captain pulled up a video file, muted the volume and pressed a large play symbol. The Doctor watched intently, as it showed footage from a security camera, as a ship crashed into the central bazaar, before it exploded and sent a wave of energy in every direction. The captain paused the footage, to watch the Doctor's reaction, who appeared confused, before talking again.

"So, ship crashes, engines explode and the energy wipes out life. But, that ship didn't look big enough to wipe out everyone, and the energy looked like nuclear particles, which wouldn't do that much damage."

"Yes, I know, but if I forward the footage to a couple of hours later…"

The captain used a dial to move the video forward, before playing it at a normal speed. In the burning crater at the centre of the flattened bazaar, there was a quick flash of what looked like smoke, flying away from the crash site. The Doctor was drawn to the video, shoved the captain away and controlled the screen himself. He repeatedly played the footage, as the trail repeated itself over and over. The captain moved back again, before whispering to the Doctor.

"We managed to get hold of some scans from a couple of minutes before that footage, and Xena Control confirmed it. Something… something was in the rubble. We can't figure it what it is though. Any guesses?"

The Doctor held his sonic screwdriver to the screen, the screwdriver making its pulsing green light. It caused the footage to play at a frame-by-frame rate, which the captain appeared impressed by. However, the movement will still too quick and the Doctor used the screwdriver again. This time, it was even slower and they could pick up the rough silhouette of the mystery 'something'. The Doctor paused the footage and superimposed the picture, zooming in closer. Finally, he could make out the figure of it. Its appearance shocked the Doctor, whilst the captain squinted and tried to make out what it was. The Doctor stumbled over his words, and it was Amy who broke the stunned silence.

"Doctor? Do you know what it is?"

The captain turned to the Doctor to see if he did, as the Time Lord covered his face with his hands. He eventually pulled them off his face, instead wrapping them around the back of his neck, pointing his elbows outwards.

"Doctor? What is it?"

"It's… it can't be…"

The Doctor rushed back to the screen and inspected the still-image closer, confirming his thoughts and guesses.

"I always thought it was a myth, Amelia. An ancient myth that I heard back home, but… at the moment… it looks so real. Like they described."

The captain took Amy's turn to question the Doctor.

"Doctor, whatever that thing is, it has wiped out all life on this planet. My men, my soldiers are at risk here, so I have a right to know, what is that?"

The Doctor spoke in a harsh tone, conveying all the fear and tension in his voice.

"That, Captain, is the stuff of nightmares. If the Time Lords were right, that is the most savage and dangerous beast in existence. They're called the Barbarus. And we need to leave this planet… immediately!"