Luminosity
"Know this, Time Lord, you are not alone." Those damn words kept echoing in his head, sending a burning sensation down past his two hearts and into his stomach. Martha Jones had demanded answers, demanded to know if those words were about her. Then in that alley he tried to explain what had happened, the great Time War, his destroyed home world, but deep down there was a lingering spark of hope. Maybe, there was a chance, maybe just one had survived.
Time passed in stuttering steps, adventures that ripped him from one moment to another. Companions passed, returned, and left him again. But those words they lingered like a scar on his mind.
After the "thing" on Midnight that had stolen his voice, Donna's warm embrace, but mocking words. The scar was reopened, Donna couldn't understand his pain, the power that he had lost. He had retreated into the TARDIS, leaving her to enjoy the remaining days of vacation. He sat against the warm core of the TARDIS, letting his mind wander in the safety of its heart.
There among the light and warmth, there was a cold dark fleck, so small he had to stop and look it over several times, before dawning realization brought him even closer to it. The fleck shifted and moved away, squirming away under his scrutiny. He came back to himself, the warm core to his back, and Donna kneeling beside him, her eyes full of concern. He shoved off from the floor, energy spilling out of him.
"This old friend of mine once mentioned a beautiful world, with an orange sky and twin suns." A bright smirk crossed his face. Donna stood slowly, her smile trying to hide her concern.
"Are we going there?"
"No," The Doctor turned and spread his arms wide, "Been there all ready!" He brought his arms down and sent them hurtling through time and space. His mind tracing the course of the dark fleck, he grin turned dark, he was going to chase after that dark fleck till his hearts gave out.
"You know, Donna, how people are like grains of sand?" She nodded and clutched at the console, struggling to keep her feet.
"Your point is?"
"Time Lords used to be like that, tiny dark flecks of energy, absorbing and generating." His grin widened, "A billion dark flecks."