You will always think of her as your companion.
It's the way you are with all of your companions, all of the ones who have traveled with you. They never stop being your companion, never gain a "former" in front of their title, not to you. Once they step foot in the TARDIS and become yours it's all but impossible for you to give them up.
Even though now you're certain she's ready to give you up.
You sit in the console room with her key between your fingers, turning it over and over. She gave it back to you when you told her you'd need to make more copies of it. The Master had destroyed yours and Jack's, of course. Pieces of the TARDIS; you were able to feel them break as if he were tearing off your fingernails.
He relished in your pain.
But now the key is just Martha's key, the other TARDIS keys made from it easily. It still has the little chips on it, still has the perception filter that kept her alive when the world was too dangerous for her to be anything but a legend, a walking ghost along the streets of Earth.
She was invisible because she had to be.
You look down at the little chips, the grooves in the key that could've come from anything, and you wonder what parts of her chipped off, as well. Your brilliant, broken companion. Like the key, you modified her and used her and now she's invisible even though she isn't wearing it anymore.
You close your eyes and grind your teeth. No, she felt invisible before she put this key on. She was invisible to you.
"She loves you, you know." It was Jack, of course, who came up to you as you set the keys and ground them into place. Your hand slipped a little, but you managed not to break anything. You can't figure out what made Jack approach you. Maybe Martha said something to him---no, no, that's not like Martha. Jack's always been a mystery. He had his own reasons.
At the time, you glanced at him over your glasses quickly, and then went back to your work. You thought about playing dumb, but after everything you three have been through it feels like it would be more of an insult. And not just to Jack.
"I know." That was enough for Jack at the time and he left without another word.
She opens the door to the TARDIS and steps towards you with a purpose. You do know, you think, even as she's grown layer upon layer over herself for protection. Of course you know.
She extends her hand to take the key and you reach out to give it to her. Maybe you've always known. Maybe it's been easier to know and not to admit it because that would mean you have to do something about it. That admission to Jack means you can't just hang in limbo. You have to decide if you want----what you want.
You don't want Martha to be invisible.
She's too brilliant. She's done too much. She means too much. You'd still be a pet of the Master's and your favorite planet would be a cinder if not for her.
She's everything that you love about humans rolled into one person. Brave and smart and creative and occasionally silly and a little bit foolish and overly ambitious and strong and a dreamer and imaginative…she falls in love too quickly and she clings to the things she cares for too tightly and you'd never, ever want her to change.
You take the key back, pull out your sonic screwdriver, and wave it over the modifications. The cloak the key held vanishes instantly and it becomes just another TARDIS key, albeit one with scratches and old wounds.
Then, you hand it back to her.
"You don't need to be invisible anymore."
Muse: The Doctor (Ten)
Fandom: Doctor Who
Word Count: 658