In another world Martha is alone. She slides across the stars and opens her eyes and is suddenly, achingly alone.
There's no explanation for waking up in a parallel universe, other than the usual wibbly wobbly timey wimey stuff, but this time—this time there's no Doctor to explain that to her either.
She wants to find the closest thing.
She goes looking for Rose, and for the human Doctor, but instead she ends up with an inky address scribbled on the palm of her hand alone in the backstreets of Leadworth.
A girl with bright red hair is stumbling out a pub, and her name lights up on Martha's lips before she can begin to remember why, and she's glowing, and—and Amy, Martha's calling.
The girl stops, separates from the tall beefy bloke she's clinging to. Fumbles over to Martha across the empty road, high heels clicking in the dark.
"How d'you know my name?" she whispers, close to Martha, warm, breath boozy, and Martha answers, "Let me tell you."
They'd met once, in the right world, the one with the Doctor in it. Amy had been older then, and tired, and married, and tired of being married. Martha called the Doctor and Amy came along because "Christ, I had to plow an entire bloody cornfield just to get his attention, and all you have to do is ring him! Bloody hell! You must be brilliant!" The Doctor's—the new Doctor's eyes had lit up at that, and he'd said, "Martha Jones—she's a star." Winked at her like it was an inside joke.
The husband shook her hand, a nice fellow, "Pleasure to meet you." He was a clever bloke, and resourceful, and cheerful, and Martha guessed correctly that his only real problem his whole life long would be that his wife couldn't quite stop being in love with an alien. Ah, well. What could you do.
Rory made a bloody good nurse, too, and said she was the nicest doctor he'd ever worked with before, and shot the Time Lord a pointed look as he did.
Before they left, Amy gave her a hug—the height difference was staggering, God—and whispered close in her ear, "I like you best, Martha Jones." She pulled away, and of course there were tears in her eyes. She squeezed Martha's shoulders. "I get the feeling I won't see you again," she said, looking off like she wasn't going to see much of anything anymore, and some inexplicable part of Martha almost replied with, You're wrong.
The Amy on this planet is young, very young, nineteen-year-old young, and there's a Rory but he's not really in the picture yet. Martha expects it'll be a few more years and then the universe will take its course.
The moon lights Amy's pale skin, and her eyes are shadows as her lids flutter closed. Martha's watching Amy's hair splayed out in the dewy grass when Amy whispers, "Do you miss him?"
Martha starts, "I—" Stops, starts again, "We always miss him." And she expects that in another world, Amy Williams really does.
This Amy shifts and reaches for her hand in the grass.
Amy's skin glows when Martha glides her hands up Amy's ribs, pearl and warm under the morning sun, and rose petals rise up to meet her touch in whatever trail that Martha traces. Her lips are red and flush when Martha kisses them, and her jaw slacks open quickly, wet tongue waiting there, and in the sun there are golden lights in Amy's hair. Legs tangle in white sheets, Martha gasps at Amy's fingers on her neck, and when Amy comes she arches into the sun, into the stars, into another world.
Maybe Rory will stay out of the picture a few years more.