"Out of their great evil some good must come." The 4th Doctor 'Genesis of the Daleks'
Martha and the Doctor stood at the Tardis Central control console, leaving behind them a depression-era New York almost devastated by the Daleks.
"Wherever it is we're going, just promise me that we won't meet the Daleks again," said the girl, with feeling.
The Doctor looked up from his controls. "No guarantees," he said. "They are the ultimate survivors. I thought they had been wiped out many times before. I was wrong."
"Just thinking about them gives me the willies. They're horrible."
"It would have been better if they had never existed."
The Doctor opened his mouth automatically but no words came out. He pursed his lips and looked sideways at his companion.
"What?" asked Martha.
"Well..." He ran a hand through his hair. "That's a different kettle of fish. Even the Daleks might produce some benefits."
Martha snorted. "I can't see how..." Then she saw the Doctor's expression. "You're going to show me, aren't you?"
His hands worked the controls.
A high hill overlooking a ruined city. The landscape was bleached bone-white. Overhead a massive sun boiled crimson, suffusing the air with a pink glow and choking heat.
The Doctor spoke. "This is Arcadia V. Once the home of a wonderful culture. Destroyed in an instant. There was a great battle fought near here. In the Time War. The Daleks tried to engulf my people...us...with a new weapon of theirs. They stole our technology and created a stellar-manipulator. They ambushed us. Launched the device into the Arcadian sun to destroy us." The Doctor pointed to the red giant overhead. "But the device was a million times more powerful than they had calculated. Arcadia went nova in one of the greatest astronomical explosions of all time. The Dalek fleet was annihilated in the blast. Most of us managed to dematerialise just in time." The Doctor paused. "Most of us..."
He shook his head and became brisk again. "The four closest worlds in the system were swallowed up. Life was extinguished on the remaining five."
Martha looked down into the valley containing the twisted chrome and blackened metal of the ruined city. "That confirms what I said about the Daleks, surely."
The Doctor looked pensive. "Perhaps. But when Arcadia exploded it could be seen from light years away. Even from your own world."
Martha frowned. "I don't remember seeing it. I don't think I've ever even heard about it."
"Oh, but you have." He took her hand and led her back to the Tardis.
Another hill, this time looking down on a village of adobe buildings and small minarets.
It was a beautiful twilight evening. The moon was high and the sky streaked with crimson.
The Doctor pointed skywards. "Arcadia," he said. On the other side of the sky from the moon, almost directly over the village, a star burned magnesium white. It was about a quarter the size of the moon and cast its own shadows. "It's at its height now. It will fade back to nothing in a few days. Given that it's about twenty thousand light-years away its pretty impressive, don't you think?"
Martha nodded. She was about to ask the Doctor the point of all of this when there was a movement on a nearby crest-line. A group of figures, silhouetted in this light, were making their way down towards the twinkling village. They were three bearded men dressed in robes and accompanied by pack mules.
As they disappeared from sight Martha felt a tingle run down her spine.
"Doctor, where are we?"
"Oh, the Middle East...somewhere," he said, airily.
"What is that village down there? What's it called?"
"I can't remember..." the Doctor scratched his neck and looked evasive.
""What's the date?" asked the girl in a quiet voice. She stared him in the eye.
He was defeated by her. "Well...approximately...AD Zero...."
Martha gasped. The star...the three men...the village...AD Zero...
Her eyes brimmed. "C-can we go down there..."
The Doctor put a finger to her lips. "Better not. This is a fixed point in time. Probably the ultimate fixed point in your planet's history. We should really be going."
The Doctor led Martha back to the Tardis. They paused at the doorway to look back on the scene.
"Happy Christmas, Martha."
"Happy Christmas, Doctor."
"And a Merry Christmas to you all at home." The 1st Doctor 'The Feast of Steven'