Martha had seen the blond woman out of the corner of her eye every time she'd been on Earth since she'd met the Doctor. The woman had never come particularly close or done anything wrong - she had just always been there. Kept in the shadows and whenever Martha went over, she had disappeared as though she was never there.
So, once again Martha Jones was on Earth, and once again the woman stood there. Only this time was different to all the rest. The woman was not crying as she normally had, instead she stared at Martha, almost signaling her to come over.
"I just need to go somewhere," Martha told the Doctor and Jack, "Don't follow me."
"You alright?" Jack asked curiously.
"2 minutes," Martha replied, hurrying off to where the woman had walked to - down a deserted alley way. Soon she was in the alley, standing opposite the woman.
"Bet you're wondering who I am, what I'm doing following you around," the woman said.
"Well yeah, actually."
"Well, I'm no one. No one you really need to know about anyway."
"What's your name?" Martha pressed.
"What? You going to google me, try and find out who I am?" The woman snorted, "You won't find out much. I'm dead, have been for a couple of years, apparently."
"What do you want?" Martha repeated.
"What I want? Only that you can do two things for me. That guy you're with, the one in the suit and converses - you stay with him for as long as you can. Make sure he's never lonely, look after him."
"What's that to do with you?" Martha asked rudely.
"To me? Peace of mind that someone is looking after him, someone really cares about him. And the second thing - I need you to tell him something in the future. Tell the Doctor I lied at Bad Wolf Bay. Her name's Jenny."
"When exactly do I tell him this?" Martha asked, "And how do you know who the Doctor is, and who are you, you still haven't explained that to me."
"The TARDIS will tell you when," the woman said as she disappeared into nothingness. Martha shook her head, returning to the Doctor and Jack, thinking nothing of the woman. She convinced herself it had all been a trick of the light, a prank. It didn't stop her feeling guilty when she left the Doctor a year later.