Martha peered around the door of the TARDIS out at the alien world.

"Why's it look like a quarry?" she wondered aloud.

The Doctor's head popped out the door. "I dunno. Lots of alien worlds are rocky." He gave her a glare. "I show you something amazing and you have to pick out what's wrong with it. Are you sure you aren't Welsh?"

Martha laughed. "Alright, let's go explore this bloody amazing alien world of yours, eh?"

"That's better." He gave a definitive nod and grinned at her.

"So where are we?"

"It's called Lonryg, and the year is 248,076," he explained, walking out with her and locking the TARDIS behind her. Shoving his hands in his trenchcoat pockets, he strolled alongside her as they made their way to the marketplace ahead. "Every year they have their annual market fair and it's the only place in the whole universe to get hullfreydlig ice cream." His wide smile gave his anticipation blatantly away. "Martha, there's nothing that tastes like it in the whole of space and time."

She smiled back, scuffing her boot in the dusty road. "They have ice cream on this planet?"

"We-e-ell, no, they don't call it ice cream, per se, and it's not like they have cows, but it's pretty much the same thing. Only it comes from something that rather looks more like a duck."

"Uh. Huh." Smile gone, she dropped her chin to look at him warily. "A duck? Is that what a hulleyfrig is?"

"Hullfreydlig. No, that's the berry they harvest for the market fair and flavour the ice cream with."

"Ohh."

Lost in conversation, the Doctor autopiloted them to the ice cream stand and wasn't exactly paying attention to where he was going. Not that he really needed to. He'd been to the Lonryg market festival more times than he could count. So when he and Martha turned the corner, he didn't see the couple they nearly smacked into.

"Oh, terribly sorry!" he immediately blurted out, and then he caught a look at them.

The gorgeous blonde with the perfect teeth, a ton of mascara and a red hoodie. Her wide smile flashing as she assured him, "No, it's quite alright. Don't worry about it." The tall man with the piercing blue eyes, big ears and leather jacket. His hand tightened on the girl's as he grumbled, "Next time watch where you're going," and tugged her past them on their way.

It was all the Doctor could do to remember to breathe. He stood frozen as Martha turned to watch the other couple walk away, her eyes wide and her jaw dropped.

"That was..." she trailed off. "I thought you said she was gone. And she didn't know you. Who was that man she was with?"

The Doctor vaguely waved a hand to hold off her comments and bent over to lean his arms on his thighs and catch his breath.

Catching the hint, Martha didn't say anything and waited for a moment for him to compose himself.

After a minute, he stood back up and Martha stepped over to link her arm through his. "Come on, Doctor. I think you need some ice cream."

Back on the TARDIS, the Doctor leaned back in the jumpseat, Rose's blue shirt clutched in one hand. It'd become a staple of the control room recently, although he still had no idea how it'd gotten there.

Martha hadn't pushed and now sat sideways on the bench, facing away from him, knees bent, quietly flipping through a book on the respiratory system of the Silurians.

Eyes fixed on the shirt in his hand, the Doctor said finally, "She is gone. It's a time machine, remember? That was a previous Rose."

She turned, looking over her shoulder at him. "Oh, right." She was quiet for a moment. "ButÐ"

"The man with her was me," he broke in, softly.

"I don't understand."

"Time Lords, we, um, have this thing." He sighed, breaking his gaze from the shirt to look at her. "I told you how old I am. Part of the way we get to be that old is that instead of dying, we regenerate. All the cells in my body change and it's like you end up with a whole new person. New face, new body, new tastes, new personality. But still inherently me with all the same memories." He paused. "And affinity for bananas, apparently."

Martha turned back away, sat and then turned to him again. "Seriously?"

He chuckled. "Seriously."

She nodded thoughtfully. "That's pretty handy, I suppose. Indefinitely?" she wondered.

"No. Twelve times and then kaput."

She smirked. "That's a pretty long time for kaput."

"I'm on my tenth life now," he added. "Plus there are still some things that can kill me rather permanently, so don't go thinking life or death situations lose their meaning or anything."

Realisation came into Martha's eyes. "So Rose didn't know you cause she was with the old you and hadn't met the new you yet?"

He sobered again. "Exactly."

"I'm sorry."

A thought popped into the Doctor's head. "How did youÐ?"

"I took a glance in her room and saw a photo of the two of you," she explained, guiltily. "Sorry."

After a few minutes he stood and glanced around the room a little awkwardly. "Well, er, thanks for listening. Think I'm gonna go... go."

Martha's eyes followed him out of the control room. Poor sad man. But she'd listen when he wanted and not ask questions when he needed and just be his friend as best she could.