It was like Stockholm Syndrome.
She knew he'd have a right laugh at that if she told him, but it was the truth. The Doctor was her captor and she, Martha Jones—the always inconsequential, naïve Martha Jones—was his captive. Martha smiled tightly to herself, realizing that even the TARDIS played a role in all of this madness. That blue wooden box of miracles, bigger on the inside in so many ways, link to impossible worlds and galaxies—that box was her prison.
She couldn't think of anywhere else she'd rather be trapped, though. It was a beautiful prison. And journeying to the rim of the universe and back, always running from one adventure to the next—it was the stuff of dreams.
But for all its wonders, the TARDIS couldn't do one thing.
It couldn't tame the storm of jealousy that ravaged Martha's mind every time the Doctor mentioned her and that distant, yearning look came into his eyes. It couldn't stop her from thinking that she was only second best, and that the Doctor would never think of Martha Jones in the same way that he did Rose Tyler.
Unrequited love. That was new.
Martha turned the TARDIS key over in her fingers and enclosed it in her right hand, pressing it close to her heavy heart. She could always leave. She could always leave the Doctor and go back home, just like her mother was constantly begging her to do. There was always that. After all, no one had forced her into this; it was a voluntary imprisonment. But she chose to stay in the end, just as she had chosen to board this ship with her beloved Doctor—albeit, a bit more aggressively than she would have liked.
But she fought for her place beside him. She deserved a place at his side.
"Martha!"
And who knew? Maybe in time, the Doctor would come to see Martha Jones not merely as a barely adequate sidekick but as an actual companion. She, too, could dust away the cobwebs in the farthest reaches of his soul; she, too, could keep at bay his demons of solitude and loneliness. She could learn how to help. What made her so different from Rose? Wasn't Rose Tyler human, too?
"Martha Jones!"
Nothing could compare to the Doctor. He was something different…and beautiful. And Martha loved him.
"Time Lord to human, come in! Martha Jones? What's going on in that head of yours?"
Martha's eyes cleared, and her gaze instantly lit upon the sharp, angular features of the Doctor. He was staring at her curiously from behind his spectacles, and she noticed his hands had stopped working at the TARDIS controls. She shook her head. "Nothing. Just…thinking."
"Thinking! Thinking's good. I occasionally do a bit of thinking myself. More of a pondering…contemplating type of thinking but it's all the same, eh?" He swallowed, and it was obvious to Martha that his idea of thinking involved reminiscing about past events…events which undoubtedly involved Rose Tyler. "But now's not the time—I need an extra pair of hands! Enough thinking, more doing! Come on!"
"Where are we going?" she inquired, composing a half-hearted smile. Martha hastily slid off her seat and stumbled over to where the Doctor stood.
"Somewhere we've never gone before."
He smirked at her, and Martha could feel her heart shattering. It didn't matter how much it hurt—she wanted to play this game. Just one more time.
The Doctor was her captor and she, Martha Jones—the always inconsequential, naïve Martha Jones—was his captive. Held captivated in his wondrous, fearsome, impossible, beautiful spell.
Pressing down on a nondescript lever, the Doctor bellowed, "Right, then. Allons-y!"
Allons-y, indeed.