"Vanishing?", her voice echoed, a certain amount of shock clearly to be heard from it. She didn't like the image of him vanishing just like that, although she had no idea how or why this should happen.

When he heard her concern, he looked up and focused away from their game of checkers.

"Oh, right, I forgot. This I might just be able to tell you about.", the Doctor set out to explain, "A rather sudden interference with time has occurred, and it has all to do with the event that will happen this very evening. Something - or someone - is bound to put your life in danger, and..."

He hesitated for a bit.

"Well, if you do not make it out of that alive, you will never grow up and become my companion. And if you do not become my companion, you will not be around to save my life from that one lethal danger, which in the end means that I am not around anymore at my relative present time that is now to you and me."

Sarah listened carefully, but still gave him a confused look. She wasn't all that sure if she was lucky to hear more when he continued his explanation.

"So, this bracelet here", he said and tapped at the wristband, "creates a personal field of temporal grace. It prevents time from catching up with me so that I can go back and avert the side effects of the original event – if not the event itself – which in turn will allow my timeline to stabilize again."

"So you're saying...", the young girl tried to get the gist, "that you're a time traveler, and you have come to save my life today to save your life in the future?"

He grinned and nodded excitedly. "I knew you would be able to follow me."

Sarah smiled back at him, but not because she was glad she could make sense of his words. No, much rather she was amused by the very idea of what he was suggesting.

"But that's impossible! Time travel isn't possible!", at first she laughed, but in the end she just had to accuse him.

"You're lying!" That was her conclusion, and he had to be thinking that she was still much of a child to simply buy into an explanation like that.

"Oh, but..." The Doctor appeared to be fairly disappointed that she wouldn't believe him. His mouth stood open as he struggled for something convincing to say. "...That is the story." He thought for another moment about it, and eventually a smile spread on his face once more. Plus, this time, he tapped the side of his nose when he said:

"Is it really a lie if it's a good story?"

At first Sarah didn't know what to make of this gesture, but the challenging grin that accompanied it heavily suggested that he didn't intent to tell her truth or lie and just let that bit of information remain a secret. And yes, in a sense Sarah could see that stories were told because they were interesting, and whether they were real or not never mattered much. Except what he had told her just now was not a tale of old, and if it was true then both of them were in serious danger, weren't they? But even though it had been he, himself who had stated it, he did not seem to be troubled by his possible vanishing very much. Actually, Sarah would say he looked rather relaxed. Maybe even more so had the turn of tables not suddenly put him into the losing position in their game of checkers.

The Doctor's look returned to the board only for a few seconds, but instead of continuing their play he addressed Sarah again, wearing now a quite intriguing expression on his face.

"What would you say if I also told you that I'm an alien – not from here?"

The child pondered his question for a little while, unsure of whether she should take him seriously or not. Eventually, she decided to go with it, because she wanted to hear what other story he had thought of. "You mean you're not from Great Britian?"

Her guess only appeared to amuse him. "My dear, little Sarah, I'm not even from your solar system. I come from a planet called Gallifrey, in the constellation of Kasterborous, and my people are among the furthest developed species of the universe." Eyes wide open he expected her to be impressed.

Sarah was still amused by what she heard. Even though she did not find his words to be very credible, she would easily agree that they were quite enjoyable to listen to. "There is no way you could prove your stories to me, or is there?", she tried to challenge him. Of course the child did not expect much of a response, but then the Doctor lifted a finger to indicate her to wait and not to jump to any false conclusions.

"I just might.", he said, and began to search the few pockets on his clothing. When it seemed that he didn't find what he was looking for, he got up and went back to the clothes hanger where he had left his coat."Yo-yo? No, too common. Spectromixer? Too complex. Jelly Babies? She's already had of those… Hmm..." His voice, as coming from the hallway, was distant and quiet and she was just barely able to make out the words while he searched the pockets of his waistcoat. "I wonder if the sonic screwdriver would convince her..." Although it sounded like he was still talking to himself, he had said the last sentence loud enough for Sarah to hear it easily from the living room.

"What's a...", she tried very hard to use the very same word and pronunciation as he had, "What's a sonic screwdriver?" Whether it would convince her of anything or not, her curiosity was definitely invoked.

The Doctor reappeared leaning back into her view from behind the living room door frame. He smiled as wide as ever and presented to her a small, metallic, roughly pen-shaped object. "This is!", he exclaimed in his almost constant cheerful manner, before making his way back to the couch. Then, when the Doctor sat back down, he passed the object into the child's hands.

Upon closer inspection, Sarah found the pen-like tool to consist of several turnable parts and a red-colored, circular head piece. Curious and fearless as she was she tried to shift and turn what she could and see if it did anything, but the tool did not reveal its purpose right away. However, after a bit more of trying around with it, she found that the piece which connected to the tool's head could be pushed down and when she did, the screwdriver suddenly emitted a high-pitched whirring sound. This unusual noise was so displeasing to her ears that Sarah decided to let go of the tool's part immediately, which luckily turned it off, too.

Holding the strange thing back up into the Doctor's field of view, she concluded: "It makes a noise."

That, however, didn't lift her confusion in any way. "But, what's it good for?"

Her play partner looked up from the checker board, just done with his move – whichever that was – and all too eagerly listed the tool's functions for her. "Sonic waves can be used for all sorts of things. Depending on the situation, and with the right frequency set, they can loosen screws, cause disruptions in complex circuitry or might even jam certain transmissions at close range. Given the knowledge how to use it and when, it can be an all-purpose tool."

"Oh, that is clever..." The child still didn't quite understand how it worked, but she knew that bats used sonic waves as a sort of radar, and the radio was a pretty nifty invention too – so at least she felt like what he was talking about was a very plausible concept. A concept which she might even be able to grasp if she would spend some more time learning about it.

"I believe it's your turn now."

Impressed with the concept, Sarah found herself staring at the sonic screwdriver with a greater curiosity than before when the Doctor suddenly prompted her to finally resume their game of checkers. Oh, right. She remembered that she had been winning before. Now it was time to do so. Finally, the girl managed to turn her sight away from the tool and lifted a hand to take the piece she had been looking at earlier and wanted to make the move that would fetch her another one of the Doctor's black coins, but there she found that, unexpectedly, this move wasn't possible anymore. One of his pieces blocked the path she had laid out, and she was almost certain that it hadn't been there before. Slightly put off course by this discovery, she decided to count the pieces on and off the board again and found the numbers to be slightly, but definitely wrong now.

Her eyes widened and her mouth stood open. Oh, she couldn't believe his boldness!

"You've moved the pieces when I wasn't looking!", she accused the Doctor, got up and pointed at the board.

He made a surprised face and looked around as if there was someone else she could have accused instead. "Me? But you were looking all the time, how would I have done it?"

"I wasn't looking when I was busy with this… thing of yours!", Sarah told him straight away and she was getting quite upset now – or, at least that was what she wanted to look like. However, one part of her was very well aware that this was just a game, and not only was it a bit unreasonable to get upset about it, but she had considered cheating for herself earlier, too. So even though she was a bit angry, she did not take the entire situation too seriously. And that was when the child's mind struck an idea. She held up the Doctor's strange tool to him once more, then hid it behind her back.

"And because you were cheating, I will keep it now!", she announced, a wide grin forming on her face.

Somehow, he didn't look too surprised by her action, but nonetheless the Doctor set out to protest.
"But you can't keep it, you don't even know how to use it!"

A chuckle evaded Sarah when she proudly presented the sonic screwdriver for the very last time, pushing down the neck piece of the tool to active the high-pitched whirring sound for a few seconds.
"Sure I do!"

"Alright fine, but I need it still." Now the man was getting back off the couch, too, and holding out a hand for the child put his belonging back into. "Come on, Sarah, give it back to me.", he demanded, but at the same time he had this impish smile on his lips and was leaning slightly forward, as if he would reach out for it by himself, anytime.

Sarah had a feeling that it could be just too easy for his tall figure to simply leap over the living room table and grab her before she could get away. So to prevent this from happening, the young girl carefully and slowly backed away, and moved around the table until she knew that the room's exit lay behind her. Challenged as she was, she was still smiling widely when she shook her head and refused.

"No."

"Sarah…!"

He also began to slowly cross the distance she had built up, ultimately forcing her further away and towards the door.

"No!" Even though the Doctor moved as slow as she did, he was crossing a greater distance at the same time, so she began taking bigger steps backwards. She got as far as to make another two or three steps, but then she eventually turned around and ran off!

"Come back here, Sarah!" At first, the tall man didn't follow and just shouted after her. But Sarah wasn't just done yet with her tease. She stopped once more standing in the door frame, and boldly stuck out her tongue.

"You're not getting away with this, do you hear me?"

And - would you look and see – the Doctor was after her within the second, chasing the child around the house!

Of course, the little girl played her knowledge of the house's layout to her advantage as best as she could. For instance, she knew that the kitchen was connected to the dining room, and both of them were connected to the hallway, which allowed her to run a circle through them. Even the round table in the dining room was useful to her, because she could fit below it and between the chairs while the Doctor had to take the long way around it. So maybe he could cross a greater distance in less steps thanks to him being a grown-up and all, but Sarah was much more agile on her short legs. Not to mention that she had good stamina as well. She kept going through the dining room and kitchen in the aforementioned circle for a while until the Doctor had realized that he wasn't going to catch her this way. Instead of continuing his pursuit, he stopped in the hallway waiting for the child to make another round and run straight into him. And Sarah almost had, except that she had noticed him standing there just in time and doubled back before he had any chance to go after her again. Which he didn't do – instead kept waiting for her next round. This time she, too, tried to be cleverer and stopped in the doorway between the two rooms, where she was, in terms of layout, on the opposite side of him. She listened for the sound of his steps coming after her, but except for her own bit of panting it remained silent. Sarah giggled to herself. She had absolutely forgotten how much fun it could be to play catch with adults!

"You know I will get you eventually..." Even though his voice came from the hallway, it was perfectly clear, and – if Sarah wasn't mistaken – she even heard a chuckle among the words. Sounded like he was having fun, too!

It was a bit difficult to tell, but judging by the general direction the voice had come from, she assumed that the Doctor must have moved closer to the kitchen entrance. In consequence, she moved a little further into the dining room, but all the time still listening for the sound that would give away his position. If she just waited here, he had to come for her, and if she could figure out from where, they could keep this game going.

And then – there it was! A loud thud, maybe a foot stomping down on the first step of a sprint, or a thing he knocked over with a hasty movement. Whatever it was, it made Sarah jump and dash forward, straight into the opposite direction, thinking her victory was certain because of how clever she had been.

The child was approaching the door frame back into the hallway when suddenly she noticed something reaching out from behind the open door. By the time Sarah got her feet to stop, not only had she already passed the door, but was also still sliding for a bit on the wooden floor. With an abrupt movement, something pulled her upwards and the feeling of her feet leaving the ground was so terrifying that Sarah let out a yelp. She struggled for a moment or two, before she felt two arms supporting her weight effortlessly, and eventually her shrieking turned into a loud, happy laugh, when she realized that it was all just for good fun.

"Got you!"

The Doctor, too, was laughing, Cheshire cat grin spreading on his face so wide you could fear it would split his head. Pulling the child a little closer, he shifted her in his arms a bit to keep her from falling.

And Sarah hung onto him by his neck, like she used to when Lavinia picked her up – now her Auntie didn't do this much anymore. But she had also not played catch with any grown-up in a long time. More importantly though, the distance to him which she had felt before was suddenly gone; The same feeling that had made him seem like a stranger to her. And now, she was willing to believe that he actually was and had always been a friend, no matter what time line he was talking about. It felt like they were on the same level of thought, despite of god knows how many years of age difference or experience. Such a strangely comforting sensation she had never thought was possible except among family members.

"How'd you do it?" Sarah tucked lightly on the scarf that wrapped around the man's neck, and the Doctor turned around so she could see the kitchen entrance from his arms.

Lavinia's flat brown shoes laid strewn about in front of the doorway. Tossed carelessly, for one reason or another.

"I thought you might be listening for me to make a sound. So I did. It's very simple, really.", he explained rather casually before seeking eye contact with the child from up close. The Doctor even lowered his head, trying a very begging expression.

"Could I have my sonic screwdriver back now, please?"

The only reason Sarah wasn't smiling anymore was because she bit her lower lip now, returning the expression with a somewhat mischievous look of her own. But in the end, she took mercy on him and without as much as a word in reply, she carefully put the sonic screwdriver into his waistcoat pocket. It probably didn't belong there, but the tool had a bit of a pen shape and in her mind that was where professors, engineers and the other scientific kind kept their collection of pens.

"Thank you."