There were a lot of things the Doctor and Clara didn't tell their daughter. They thought the idea of Daleks and Cybermen were a little too much for 7-year-old Elsie, they had yet to tell her about the birds and the bees, but Elsie was a lot cleverer than they thought because this Christmas, their daughter was going to find out the truth about Santa Claus.

I saw Mummy kissing Santa Claus

For a 7-year old child, Elsie considered herself to be very clever. She knew that she was leading a different life from any other kid her age. She knew that her parents were weird. They were a good of weird, but they were weird nonetheless. And Elsie knew that whenever they came to stay at her great-grandmother's place, she would find a nicely decorated pine tree in the living room and usually, there were presents underneath.

"Oh, well, Santa Claus put them there, of course," her mother kept saying to her, smiling that strange smile that she always put on when she was telling a half-truth. "He only gives presents to the nice children, so be sure to be very nice to your parents or you won't find any gifts under the Christmas tree this year."

Elsie had grown up with the story of the kind, old man with his red robes and white beard who surprised children by leaving them presents once a year, but the older she got, the more she doubted that the story really was true. She had never actually seen him, but that would change this year, Elsie vowed to herself. This year, she would find out if the story about Santa was true.

Just like he did every year, her father had parked the TARDIS in her great-grandmother's living room which had sparked the usual argument, but the TARDIS had been allowed to remain. It was just a few steps from her bedroom in the spaceship to the pine tree in the living room and the plate of biscuits on the table next to it. Elsie waited until both her parents had tucked her in and given her a goodnight kiss before she turned to her side and closed her eyes – and then she bided her time.

When her parents' voices on the TARDIS corridor had vanished and Elsie could be sure that they were no longer around, she climbed out of her bed and opened the door to the corridor. It was empty and the only sound she heard was the low humming of the sleeping engines as she made her way through the console room and towards the wooden door. She opened it just a little and then almost slammed it back shut in surprise when she heard an unfamiliar voice.

"Ho ho ho, I'm ridiculous," said a man in a very deep, husky voice.

"Shut up," her mother giggled. "I'm telling you, she suspects something. Elsie isn't a baby anymore."

"Ho ho ho, and the plan is to, ho ho ho, fool her a little longer?"

"Exactly," her mother confirmed. "Now stop it with the voice cause that's the only really ridiculous thing here."

Finally, Elsie had gathered up the courage to open the TARDIS door a little wider and her mouth instantly fell open when she took in the sight in front of her. Not only had several Christmas presents appeared under the tree, but her mother was talking to a strange man who could be no one but Santa Claus. He wore the famous red and white robes and the hat on top of his head. She wished that she could see his face, but the man had his back turned towards the TARDIS. If only Elsie could sneak across the room to get a proper look at him. But what probably astounded her the most was the fact that her mother seemed to know him. In fact, she seemed to know him very well because a moment later, Elsie felt her stomach twist into a knot when her mother reached out and touched Santa's face.

"You know, I'm strangely fond of the beard," her mother said and granted the man a strange kind of smile. "You should consider keeping it."

Elsie clapped her hand in front of her mouth when she watched her mother go up on tiptoes and kiss Santa Claus. Her mother, her own mother, was kissing Santa while her father was probably just a few steps away, somewhere in his TARDIS. Suddenly, Elsie was overcome by a loathing for this man who could just come into their house and kiss her mother. No, Elsie was determined not to let Santa steal her mother away.

She used the moment her mother and Santa were occupied and darted across the room to the perfect hiding spot under the table. The tablecloth was ideal to shield her from view.

"Ho ho ho, I could keep the beard on later," Santa suggested and there was a hint of amusement in his voice.

"You can also drop that silly voice," her mother complained.

When Santa suddenly moved away from her mother, Elsie saw her chance. She was hiding right next to his feet and as he stepped backwards, she thought of the perfect way to get her revenge on Santa for trying to steal her mother away. Elsie outstretched her leg only a little and, just as she had hoped, Santa's feet got caught and a moment later, he fell to the ground with a thud.

"Ow!"

"You're not gonna steal my mother, Santa!" Elsie shouted at him as she jumped out of her hiding place, yet she fell silent the moment she looked at his face.

Santa's eyes looked strangely familiar.

"Oh my God, are you okay?" her mother's worried voice resounded in her ear right before she knelt down next to Santa.

"Yeah, I'm fine," Santa replied, only now his voice had changed and it sounded a little less husky than it had before. In fact, even his voice was familiar now.

Then, as her mother pulled down Santa's fake beard, Elsie realized her mistake and the heat rose to her cheeks, making her blush in an instant.

"Elsie, your mother and I have something to tell you," her father announced as he scrambled back into a sitting position.

When her gaze shifted towards her mother, Elsie noticed that she now looked a little uncomfortable and it took her a few moments to put the pieces of the puzzle together, but eventually, it clicked.

"Santa Claus isn't real," Elsie realized. "You've been Santa all along."

Her father nodded, an apologetic smile on his face.

Elsie bit down on her lip. "I'm sorry that I tripped you."

To her surprise, her father started to laugh. "It's okay," he reassured her. "I'm just glad you're not gonna let anyone steal your mother away. She has a history of getting into blue boxes with strange men."

"Excuse me!" her mother exclaimed and reached out to nudge her father.

"Alright, let's not dwell on that," her father determined and suddenly, he jumped to his feet faster than Elsie or her mother could react. "Falling down has left me a little light-headed and I'm afraid I'm gonna need a good movie and lots of Christmas biscuits to get better. Who's with me?"

"I'm with you!" Elsie agreed on the spot and jumped up as well while her mother slowly rose to her feet as well.

"What about bedtime?" she asked.

Both Elsie and her father frowned at her in response.

"Our daughter just found out that Santa Claus isn't real. She's is going to need some consolation. Isn't that right, Elsie?" her father asked and when she looked up, she found him winking at her.

"Absolutely!" Elsie agreed, pouting playfully. "Or I'll probably have nightmares."

Her mother knitted her eyebrows at them both for a moment, but when a soft smile spread across her face, Elsie knew that she had given in.

"Alright," she agreed. "You two take the biscuits. I'll join you in a few minutes with hot chocolate."

"Yes!" Elsie exclaimed happily and she grabbed the large plate of biscuits before she and her father headed back into the depths of the TARDIS.

Even though Elsie had suspected that something about the story of Santa Claus wasn't right, she had to admit that she liked the truth about him even more than the fairytale she had been told.