"What do you see?"

Martha looks up from her book, startled by the Doctor's sudden question. What does she see? What sort of a question is that? She considers it for a moment, wondering if maybe he's taken something of hers and hidden it. He often did that, although she'd thought he'd have learned his lesson after the shouting she did after he hid her hairbrush in the Frozen Gardens of the Interplanetary Confederation Headquarters on Glacies Plagiarius VI.

"What do you mean? I can see you, the TARDIS controls, the door…" She trails off, unsure of quite what he's getting at.

"No," He smiles and shakes his head. "What do you see, when you look at me?"

Martha flushes. As if that makes the question any easier to answer, she thinks. "I still don't get what you mean. I see you"

"Humans! You ask a simple question…" He exclaims, stamping his foot in exasperation. "Adjectives, Martha! Describe me!"

"Oh." She flushes again, feeling silly for having read too far into what really was a simple question after all. "Um…tall, brown hair, skinny…"

"Is that it?" The Doctor looks disappointed, and sighs. "I've never asked a human that before, and now I wish I hadn't"

"I'm sorry."

"It's not your fault." He says, in what Martha considers a slightly patronising way. "I just didn't realise you were so simplistic"

"I am not simplistic!" Martha objects, her voice becoming challenging. "So tell me, what do you see when you look at me?"

Now it is the Doctor's turn to think. "I see…time. I could tell you your hair colour, your eye colour, your figure…" He pauses, thinking how best to phrase the next sentence and Martha squirms. "I see all that, but I don't see it, if you know what I mean"

"If I know what you mean?" Martha repeats, incredulously. "Doctor, I have no idea what you mean. None at all. You've gone beyond the vaguely enigmatic and into the completely bloody impossible"

The Doctor frowns, "Really? I understood myself." he sees Martha's frustration and decides to try again. "I see everything. Like in that film with that man and the boy. The one where he can see dead people."

Martha's mouth drops open, in complete and utter astonishment. "When you look at me, you see dead people?"

"No!" he says, running a hand through his hair, making it stand on end. "I wish I'd never started this now, it's getting ridiculous. Forget I said anything at all"

"Oh, no way!" Martha exclaims. "You can't just say things like that, then leave a girl hanging. It's ungentlemanly"

The Doctor's mouth twitches in amusement, "Well, Miss Jones, if it's ungentlemanly…" He pauses yet again, before a grin breaks out. "I can see you. Everything about you. I can see your physical features, but they're not important. What I see is time. When I look at you, I see your past. When I look at your face, I can see how you looked on your third birthday, when you didn't get the bike you wanted. When I look at your mouth, I can see your first kiss, with that boy from down the road."

Martha fidgets and looks down at her lap, feeling uncomfortable. "You can see all of that? Can you see the future?"

The Doctor nods, but refuses to say any more, even though she begs him. He can see her future. He can see the look on her face when he falls for someone else. He can feel how she'll feel when they have to part. He can see her life, and also her death. He would never tell her that, of course. He never tells his companions that he always knows they'll have to separate. It would make it too real, for him especially. He likes the youthful optimism that they can be together forever, chasing adventure across the galaxy. That they'll never have to say goodbye. The Doctor has said goodbye too often, and it plays on his mind every time he takes them somewhere special.