Martha groans and flops ungracefully down on her bed. Her mother would purse her lips in disapproval at such callous treatment of furniture, but Martha defiantly doesn't care. She stares at the ceiling.
"Who was she?" She waits for a moment before laughing at herself, but a small noise comes from her bedside table, just a whisper of a sound. She rolls over and props herself up on her elbows and finds an old-fashioned photobooth strip laying where nothing had been before. She blinks and picks it up.
The Doctor is in them, but it's not the Doctor she knows. This Doctor is carefree, so happy that it almost hurts to look at him. Martha stares at the blonde girl who shares the pictures, knowing in the pit of her stomach exactly who it is. The girl has an odd face, somewhere on the edge of beautiful. Her chin is a bit too sharp, her mouth a bit too wide, but the spirit animating her features makes her breath-taking.
Martha curls up against her pillows and studies the pictures. There are four shots and the Doctor and Rose share them all, crowded into a dingy photobooth so small that Rose is sitting on the Doctor's lap. They're grinning madly at the camera, then making some of the most absurd faces Martha's ever seen. She peers at the second photo. She didn't even know somebody's face could do that. Then again, the Doctor is an alien, so that might be it.
In the third, Rose has stolen the Doctor's glasses, and Martha blinks in surprise. If she'd ever pulled anything like that, the Doctor would've bitten her head off. With Rose, he just watches her laugh, cross-eyed through the lenses; his expression is so open and adoring that the breath catches in Martha's throat. By the final picture, Rose has removed the thick-frames specs and is staring back at him, her expression just as tender. The moment caught on film is so potent that Martha can almost feel the potential brushing against her nerves. She stares at that last photo and rolls onto her back with a sigh, laying the strip back where it had appeared.
Whatever muddled relationship she and the Doctor have, it's nothing like the one she sees laid out in those four little boxes—and she knows with a sudden certainty that it never will be. She blinks back tears. No matter how badly she wants to help the Doctor, she can't pull out her textbooks and heal him. He lost something of himself when he lost Rose, and she's not sure if he'll ever get it back.
With the feeling of poking at a sore tooth, she picks up the photos again and contemplates them. She's seen that last look on his face, before. Mainly whenever he shows her something that nearly stops her heart with beauty—and then, it's almost always as an apology for whatever appalling scrape he's pulled her into most recently (if she's cataloged them, it would fill up a whole notebook).
But she's seen it, whether they were looking out the TARDIS' doors at a celestial nursery or standing in the rippling light of the three sunsets of Janus. It's a sort of awed wonder that the universe could hold something so beautiful, and in this small, brightly-colored strip of photos, it's entirely focused on the laughing blonde girl in his arms.
A knock sounds at her door, and she hurriedly slips the photos into the table's drawer. "Come in."
The door opens silently, and the Doctor steps in. His brows are drawn together, and his eyes are dark. "'Lo, Martha." She smiles uncertainly at him, and he clears his throat uncomfortably. "I may have been a bit harsh earlier."
She blinks. "Wait, are you apologizing?"
His eyes flash, and he scowls petulantly. "I was getting to it, yes."
"Um, it's no big deal. Really. I'm fine." She smiles at him again, and he nods decisively and turns to leave. "Doctor?"
He turns back around again, his eyebrow cocked inquiringly.
"Don't mention it." At that he abruptly walks out of the room, leaving Martha to stare at the door.
Ever since her first trip with the Doctor, she's wondered if she'd been doing something wrong, if maybe she'd been faster, stronger, smarter he would look at her with that smile in his eyes. She peeks at the pictures again and sighs. With a depressing sense of finality, she realizes that it isn't anything she has or hasn't done—it's who she isn't.
And there's no getting away from that.