The TARDIS was empty. She could feel the presence of all her corridors, all her rooms, but there was no movement, no life within them. There was only the humming of her engines, the whirring of her circuits, the rumbling of the machinery deep within her heart. The Doctor had left her on a deserted moorland on a planet of the far reaches of the Cassiopeia system and had gone walking, alone.
He was alone again. He had been alone for a long, long time. The length of his solitude was reflected by the darkness of the circles under his eyes, and those circles grew darker and deeper with every passing day.
She didn't enjoy seeing him like this. Her thief, her Doctor, the man who held her heart in his hands (if she had one) was lonely, was in pain, and she could do nothing. The TARDIS wished fervently that she could just talk to him again, comfort him, hold him, and let him know that while he had her, he would never be alone.
But she wasn't built that way. A TARDIS existing across all of time and space could not be confined to a single instant in time or a single point in space without causing a massive temporal paradox. While she could throw a few levers to let him know she was listening, she could never directly access her voice interface. The time when they talked had ended.
She just didn't want him to be alone anymore. He had refused to take on any new companions for years now, and his enforced solitude was taking its toll. He wasn't built to be alone like this, she knew. A Time Lord was an intensely social creature, the Doctor even more so, and to force himself to stay alone would only make him fade further and further into himself.
But maybe he didn't have to be alone. Maybe the TARDIS could find someone and make him take them along.
Or maybe, just maybe, she could make someone herself.
And slowly, the TARDIS began to formulate a plan.
It had taken time to stealthily acquire all the necessary materials for her plan, but she finally had everything she needed. The next time the Doctor parked her on some lonely shore and went walking, she began to work. In the abandoned console room, a golden streak of light snaked its way from the heart of the TARDIS and began to coil around itself in the air. Slowly, the glow expanded inch by inch, and started to take on the shape of a woman's body. Her body.
When the Doctor opened the TARDIS doors and stepped inside, he was greeted by a decidedly unusual sight. A brown-haired woman with her back to the doors was standing over the console, brushing her fingers along the many levers and buttons and screens and making small noises of contentment. Surprised and angry, the Doctor strode up the stairs towards the intruder, loudly demanding, "Who are you and what are you doing in my TARDIS?" She turned around, and he stopped dead in his tracks.
It was his TARDIS.
She stepped toward him, still wearing that raggedy party dress she had worn all those years ago, and smiled. "Hello," she whispered, in a voice bright with emotion. "Hello, Doctor. It's so very nice to see you again." Scarcely believing what (rather, who) was in front of him, he tentatively reached out a hand with one finger extended and prodded her in the shoulder. She rocked back on her heels and grinned at him.
"But how...?" he muttered, trying to wrap his head around the reality of what was standing there. The TARDIS took his hand between her two small ones, further reinforcing her solidity.
"You were lonely," she said, as if it were the most understandable thing in the world. "I made a body and I put just a little bit of myself inside. And since I liked it so much the last time, I picked this one." She paused, and looked at him with her head tipped to one side. "What do you think?" He ran his free hand through his mass of hair, trying to verbalize the maelstrom of emotions running through his mind.
"I... I don't know what to say. How... no, that's not important. Why? Why now?" he begged of her, trying to understand, and leaving the most important question unspoken. If you could do this, why not before? She stretched out a hand to his cheek, still holding his hand, and smiled again, this time tinged with sadness.
"I didn't know if I could," she said simply. "I wasn't sure I could do this, let alone create a viable body. But you were alone for so long, and you shouldn't be. And now you won't be." She let go his hand and stepped backwards towards the central console. "Now you have me. Like you've always had." He followed her up the stairs and for the first time in a long, long while, stretched his mouth into a grin. His shells were starting to crack.
Gently, he rested his hands on the console. Her console. This would take some getting used to, he thought, then asked her, "Where do you want to start?"
She smiled back at him delightedly.
And as they spun their way through time and space, he knew she'd never let him be alone. Just the Time Lord and his TARDIS, the TARDIS and her Time Lord, making their way through all of time and space because in the end, there was nothing better than a boy and his box.