A Purpose to Complete
An ode to Predestined Paradoxes, in honor of Blink. No real spoilers, placed at the end of Smith and Jones.

Everyone he ever touched had been changed.

Anyone who had chosen to stop and listen, to say a few words, to step inside his frankly magnificent time ship, had been there for a reason, even if they, or he, or anyone else had yet to discover what that reason was.

Susan had been meant to fall in love on a war-torn, backwater little blue planet, and though she hadn't known it at the time, he suspected that was why she stayed with him when her parents had, as all humans do, withered into dust. In turn, she was also meant to be there to bring Ian and Barbara on board, because the one thing they needed most was someone to open their minds to the universe.

When Vicki joined them, it was already written that she would become part of Trojan history. When Steven snuck aboard, his name was already recorded as the first and greatest leader of a civilization that would help to shape the galaxy into the first of many Great and Bountiful Human Empires. The fact they needed rescuing was merely a sideline to the cosmic balance of things.

When he met Jo for the first time, he didn't see a girl, barely yet a woman, whose bright smile and innocent manner destroyed a good day's work on fixing his dematerialization circuit. It was why he gave her the sapphire – she was hinged to be the turning point of his life. And, later in her life, their timelines would intertwine again as Ianto Jones, secretary-slash-tea boy to Jack Harkness, tried and failed to stop Harper from opening the Cardiff rift.

They all had a purpose to complete, by touching him. He saw it in Nyssa, who was orphaned in an act of survival, and so would help others to survive, which was why his ship docked with Terminus when it sought out a safe port. He saw it in Mel, whose eyes shone with the firelight that matched the gleam in Glitz's gaze, and so he nudged her down the right path. And he saw it in Ace and Hex, whose paths had intersected long before either had joined him, and which would rejoin in the past of the future when Times Vigilante took up her burden, because of one young woman he and Evelyn had helped in another life.

But there were those whose purposes had twisted out of his control. Katarina, meant to die to save their lives, but a death he would never be able to forget. Adric, who fought so bravely to buy them the time, and faced his end in silence, his brother's sash finally earned. Peri Brown, who gave him something to die for, and in return he made her into Schrödinger's botanist. Jack Harkness, dead at the end of a Dalek gun and abandoned to an empty space hub, whose destiny was already written the guiding force at the turn of the century for humanity.

He grins with exuberance, clutching the console with one hand as he reaches across, clasping hers in a firm shake. "Welcome aboard, Miss Jones!"

And he wonders in the end what her purpose will be.