A/N: This story is going to be placed on season 3 of TVD (when Katherine is running away from Klaus) with a few mentions of Katherine's past and also set after the last Christmas special from Doctor Who. Enjoy! :)

The Doctor had just left the house of the Ponds, he spent Christmas with them but he couldn't stay longer that's not who he was and they knew it. After saying goodbye and promising Amy that he would come back to visit soon he entered the TARDIS.

"Where are we going now?" he asked his TARDIS walking towards the console. He barely touched the controls when abruptly the TARDIS shook and started moving. Moments later it stopped, the Doctor promptly looked at the screens and scanned the place in which it landed.

Bulgaria, June 20 1489. "Well, interesting." He turned around, his hair getting a little messy by the sudden move. "Now, what do you have for me?" he opened the door and looked outside.

He was standing in the backyard of a big house, probably owned by a wealthy family. He looked around, no sign of anything weird. He heard a noise coming from the other side of the house, he watched as a young girl stormed out of the house.

The girl couldn't be more than 14 or 15 years old. She had long brown curly hair. She was wearing a blue kirtle low front opening with laces over, it was a contemporary dress for that time but surely made of a richer fabric which showed she was the daughter of a rich family.

She stood in front of the house, right hand on her stomach while her other hand swiped the tears from her face.

The Doctor couldn't stand there and do nothing she looked deeply disturbed, he walked towards her trying not to scare her. "Are you ok? Can I help you?"

She heard a voice of a man, she turned around heart beating faster. She was scared, she had just been thrown away, rejected by her family she had nowhere else to go and there was a strange man talking to her. It was too much to take in her condition.

She fainted. The Doctor ran next to her, making sure she didn't hurt herself.

The Doctor was holding his sonic screwdriver, he was staring at it with a concern look on his face.

The girl was pregnant.

He carried her into the TARDIS, making sure she'd be comfortable and he waited until she woke up.

"Oww" her head hurt, she remembered falling into ground. Her sight was still blurry, she looked around, didn't recognize the place, she blinked two more times and finally focused on the man that was sitting next to her.

"You, stay away from me!" she screamed and tried to stand up to get as far away as she could from the man but she was still weak and lost her balance.

The Doctor caught her as soon as she stood up and helped her sit again.

"You are safe here, can you trust me?" he told her sitting next to her. She looked at him, almost immediately noticing his green eyes, there was kindness in them. Maybe he really wanted to help her.

He saw her staring at him, he made sure she had time to think about the situation then he added "I'm the Doctor" and smiled kindly waiting for her answer.

"I.. I'm Katerina.. Katerina Petrova" she replied, "can you help me?"

He smiled gently at her, "of course"

She burst into tears, the Doctor hugged her. She was scared and she wanted to trust the Doctor, she knew she probably was crazy trusting a stranger but she didn't have a choice.

A/N: Ok so this was an introduction of how the Doctor and Katherine met, next chapter I'm going to finish telling their back story and hopefully chapter 3 will be focused on the present time. So yeah, hope you stick with me :D