Part 1: Reality Check
The Doctor and Rose stared up at the sky as a gigantic ship roared overhead, splitting through tufts of white clouds and filling the air with noxious fumes.
In the spaceship sat a small pig, its ears standing up tall, its eyes shining with pure fear, and its entire body shaking violently.
Although the outside of the ship appeared to be crashing, no alarms were blaring inside. No lights were shining. The whole crash seemed calmer than it should be.
Every few minutes, an automated, Slitheen undulated voice would come out of the speakers in a monotonous tone, in order to say:
"System Functions Normal. Planned Crash in Thames in … 5 minutes"
At that point the speakers would crackle off. Each time this occurred, the small pig would give a little jump.
Then, contrary to the nature of the faux crash, alarms did begin to sound. Red blinking lights filled the room in the color of blood. The Pig scrambled and scuttled across the chrome floor of the ship, desperate to escape. Meanwhile the Slitheen voice crackled to life once again, only this time, a note of urgency was in its voice.
"Unsighted Object. Unsighted Object. Scanners Not Registering Object. Unscheduled Crash. REPEAT: UNSCHEDULED CRASH!"
The huge metal contraption of a spaceship slammed into Big Ben, tearing off a gigantic chunk of the clock tower.
Far off in a distant room, two gigantic Slitheen Raxicoricofallipitorians stared at a small television screen which depicted the Big Ben Crash, their eyes widening in awe.
"Brother, I do not understand the alarm. We planned for the ship to crash into the clock tower. We programmed it to do so. Why did the alarm sound?"
The taller of the Slitheens stared down at his sister. "I am not sure sister. It appears the alarm sounded because as soon as the ship was about to crash into the clock tower, the radar seemed to not register it as a clock tower anymore…"
"Than what, my brother, did it register it as?" pressed Blon Fel-Fotch Pasameer-Day Slitheen.
"It registered it as … well, its too ridiculous to repeat… but it registered it as an object far more massive than it was." The tall Slitheen shrugged his shoulders, "it must be the damn faulty old machinery in that ship."
For a moment, Blon stared up at her brother, her eyes squinting in suspicion. Then "Of course," she remarked. "That must be it." Although her eyes had relaxed, a glimmer of suspicion lingered as she stared at the TV.
On it, the picture glared as it showed a devastated Big Ben belching voluminous black smoke into the sky.
YEARS LATER
Big Ben stood in its complete glory against the fading evening hued sky. The Doctor recalled seeing it be destroyed partially, sitting on the roof that he sat on now.
As he adjusted his bow tie, he recalled how quickly it had been repaired, as if overnight. He pondered on how strange that was, since it took months to rebuild Downing Street, which had been destroyed in the same attack.
Soon his mind wandered along a different track, thinking about how much he had changed since that event, and not just the fact that he had undergone 2 regenerations, but he as a person had fundamentally changed.
Eventually, the night sky darkened and faint shimmering stars began to pop up across the dark night sky. Slowly, the Doctor could feel exhaustion eating away at him. He tried with strenuous effort to keep his head up, but it nodded down. His eyelids closed…
…then snapped back open.
The Doctor's breathing became rapid and shallow. Sweat formed on his brow. Tears welled in his eyes as emotions, both old and new, tore through him. When he closed his eyes he had seen 2 words: Bad Wolf.
Then lights began to spin. But they were real, down near the base of Big Ben. The Doctor heard a scream. A familiar scream.
Running. Faster than ever before. It didn't matter that he could have just used his TARDIS which was on the roof. It was too unpredictable and this was too important. For there was fear in Rose Tyler's scream, which grew louder every yard that the Doctor bounded across.
Then he was at the foot of Big Ben. He saw a group of disheveled people covered in ragged black clothes. They all had gray skin. The tallest one was carrying some sort of writhing bundle of scratchy, moldy cloth. He turned around to face the Doctor, smiling to reveal pointed, stained teeth.
Then, suddenly, skidding sounds of rough tires filled the air as lights blasted on. One after another Black UNIT Jeep appeared out of nowhere.
"A Familiar voice rang out over a megaphone. Stop Trespassers who call themselves the Reality Checkers. We are UNIT. We have you surrounded!"
The smile faded from the tall man's face and he drew up a black hood, which shrouded his face aside from bloodshot yellow eyes. They flickered up at the clock tower face, then stared directly at the Doctor. A rough, harsh voice said…
"If you want to see he again, you'll have to find us."
Silence rang in the Doctor's ears. He couldn't evaluate the man's face, but he thought he knew who the "her" was that he had been referring to.
"How do I find you?" The Doctor called frantically.
"Thank him Doc" The voice called out mockingly. "For rebuilding Big ol' Benjamin so quickly." Then, a harsh and cruel laugh echoed across at the Doctor.
There was a large spinning of white lights. A loud scream rang out, and a piece of moldy cloth fell away, revealing a beautiful lock of blonde hair. Then, all was silent again. The group of men, and Rose, were gone.
The Doctor turned on his heel and began to march towards the jeeps were yells of frustration and anger could be heard. In the middle of it all with a megaphone in one hand was the new Doctor and General of UNIT, Martha Jones.
The Doctor did not smile. He did not run up to Martha and hug her. The Doctor did not even say hello. He walked right up to her until his face pressed up against hers.
"Who Rebuilt It?" The Doctor demanded.
"Huh?" Martha said.
"After the Slitheens invaded, WHO REBUILT BIG BEN?" The Doctor screamed.
"Back away sir, I don't know who you…" Martha began timidly.
"He's the Doctor, Martha, can't you tell?" It was Mickey Smith, and he was putting down his laptop and climbing out of the truck. "Just looked up the project to rebuild Big Ben, Someone paid huge amounts of money, and I mean Trillions, to have it done so quickly. They commissioned the reconstruction to be done within a very strict time limit."
"Who rebuilt it so quickly?" the Doctor growled.
"Oh, I dunno him, I reckon you wouldn't have heard of him either," Mickey said. "It was just some bloke named Saxon."