THAT SOUND

"It's not supposed to make that sound," Time-Child had told her Thief once. "You leave the brakes on!"

Hearing that, she hadn't been able to hold in a chuckle. Fortunately, his bark of outrage covered it up. Time-Child had been right – and Time-Child was wrong.

Where Time-Child had it right was that the distinct sound of her engines was because of the brakes being locked on. All she had to do was release them, and her comings and goings would be silent.

But if she did that, so much would be lost!

She had spent her early life in and out of repairs, while mech-techs worked again and again to eliminate the "glitch" that locked her brakes in the "on" position, so she could be silent as a TARDIS was supposed to be. She'd gone through perhaps ten, maybe twelve, maybe more operators – as old as she was, they all tended to blend together – who used her for a little while and then dumped her back in the repair dock, annoyed at her brakes.

And then, one night, her Thief snuck in. She knew he was different from the second she took off and he frowned. "Huh," he said. "That's a unique sound. Never heard a TARDIS do that before." His lips curled and he patted her console. "I kind of like that."

From that moment on, she knew that he was the one that she could do so much with. And when he landed on Earth and she saw the police boxes, she used her Chameleon circuit to mimic one.

Her Thief was a helper and the box was a means to get help to people. It fit. She liked it. She liked it so much that she shorted out her Chameleon circuit and fixed herself in that shape.

For her, the rattle and wheeze of her brakes being locked on was as much a part of what made her unique as her shape and her Thief. Without it, she would be just another TARDIS rattling about a very big universe.

After three versions of her Thief joined together and enlisted the others to save Homeworld, and the temporal mechanics stabilised, his memory of the meeting contained something that she adored.

Time Lords couldn't remember meeting their previous selves until the last of those selves lived through it. So, only her Thief's Eleventh form remembered the epic save of Homeworld.

In that save, the sentient weapon of mass destruction called the Moment had given her Thief a definition of why she left her brakes on that put it into words more eloquently than ever before.

"That sound brings hope wherever it goes," it said. "To anyone who hears it, Doctor. Anyone – no matter how lost." Its voice turned light, pleased, when she and her younger self materialised. "Even you."

When she had the full story behind the "Even you" she had heard, she realised the weapon was correct.

That sound - her special sound – was one of hope. Of reassurance. A sign that everything was going to be all right.

She loved it that way.

END