Finding Out On Your Own, a 10+11 Doctor Who fanfiction

Who am I?

"You know what?" The youngest of the two- Not that that makes him young, of course- called from behind the future version of himself, who was walking at a steady but surprisingly cheerful pace. The Doctor didn't understand. How could his future self possibly be cheerful, when he himself had a constant knot of worry and anxiety pulling at his insides. Was this what he was going to turn into? He was monitoring his every step and every word, deducing as much as he could.

So far he had come up with nothing.

"What?" The purple-coated version of the Time Lord asked a few moments later, breaking the other Doctor out of his distressed thoughts and looking back briefly, at, to be cruelly honest, a terrible time, as he could only barely dodge an unfortunately placed traffic sign. Regaining what dignity he had left, he, with an unnecessary amount of hand gestures, motioned for his past to continue.

"I was thinking, you said you didn't remember, which means that at some point we forget. And skipping the obvious, such as a possible memory wipe we might suffer through, it would be paired with another phenomenon" Making their way down some stone steps, he took them two at a time. He might be a time traveller, but he still wanted to save time.

"Go on.." The impatient voice prodded from behind him. It had fallen behind as they descended the steps, obviously not in such a hurry.

"We're crossing our own timeline here, tangling it, it's out of sync. But the vortex is clever, it can untangle it easily. So as soon as I get back into the time vortex, wham-"

"It evens out our timeline, and you don't remember. Very good."

"Thank you." He smiled. Suddenly, he took a sharp, realising breath, and fished in his pockets for his screwdriver, emptying his pockets and quickly searching the area for any technology. He disassembled a TV resting against some bins. "Exactly what I needed!" He said, sounding satisfied. "If something's letting you through, it would take massive energy, plus it would send out very specific waveforms. I could figure out how I can detect them, plus massive energy fluctuation, and use them to track whatever it is down, locate the source." He explained at an extremely rapid pace. Fiddling with a little dish he kept in his pocket for emergencies- He loved little dishes- he looked up at himself, who was fixing his bow tie, it seemed of great importance to him.

"Come and help me, then." He said with an inviting head jerk. He needed an extra screwdriver for this job, it was tricky to set such a small dish to pick up such complicated waveforms.

The eldest sat crouched, one arm resting on his knee, the other fishing for his own, green-tipped device, and handed it over. He watched as the brown-coated version of himself studied the screwdriver, twirling it in between his fingers.

"What happened to my one?" He asked, not taking his eyes off the sonic.

"I had to signal a spaceship, I turned it too far up, every fuse burnt out. The new screwdriver had a different exterior. But I've got no reason to complain." The Doctor said smugly.

The other Doctor, wearing his thick-framed brainy specs, was now using the both familiar and unfamiliar screwdriver to install and tune another tiny dish, he had to find power fluctuations at a very large scale, and little dishes do the job perfectly.

"Almost finished, give me a minute.." He said absently, pressing the green, lit tip into the wiring. "Got it!" He yelled excitedly. He jumped up from his crouched position, and ran off, following the gentle beeping of his new tracking device, his future, and quite frankly, slower version right behind him.