"What I still don't understand," said Rose for the seemingly hundredth time, "is why this regeneration thing actually happens." The Doctor sighed for the seemingly hundredth time and ran his fingers through his hair. It was becoming a new habit of his, running his fingers through his hair. It was a novelty, having big hair like this. His eighth self had had fairly long hair, but not since his sixth self had he had hair so … well, big. He quite liked it.

"Like I told you," he said, with an air of infinite patience, "it's a Time Lord's way of cheating death. Time Lords can regenerate twelve times – thirteen different incarnations – before they finally die. They reinvent themselves, if you like." He paused and thought for a second. "Bit like Madonna. Popstar, actress, children's author … same basic principle, 'cept Madonna only reinvents her image. Me, I get a new face, new body, new personality." He grinned widely. "New teeth and everything."

Rose didn't return the smile. She was frowning at the floor, apparently lost in thought.

"So … there's been … other … you's?"

"I s'pose you could put it like that, yes. But now it's just me." He smiled again, more gently this time.

"And me," Rose said, smiling ever so slightly back at him. The Doctor grinned wildly again and shoved his hands in his trouser pockets.

"Course, this new me is a vast improvement on the old—hang on, what's this?" He withdrew his hand from one of the pockets and pulled out a small, rather squashed brown paper bag. He frowned slightly, opened the bag and sniffed its contents. Then, with a similar look to the look he wore after he'd worked out the Sycorax's blood control, he fished out a green jelly baby and popped it in his mouth. "Cor, I love these. Always have, ever since my fourth self. Anyway, like I said, vast improvement. Some characteristics are the same, but for the most part I'm a new man." He swallowed his first jelly baby and fished around for another one. And another one. And then another three.

"You ARE rude," Rose remarked with a cheeky glint in her eye. The Doctor looked up with a half-surprised look on his new face – his sparkling blue eyes were wide and his cheeks, usually quite defined, were bulging.

"Whuh?" the Doctor replied, his mouth full of half-chewed sweets.

"All those jelly babies and you haven't offered me one yet!"

"Ooh, cripes, that IS rude, I'm so sorry … here, d'you want one?"

"Thanks, I won't. Watching my figure."

"Someone's got to." He slapped his hand over his mouth momentarily before frowning and trailing off. "I really AM rude …" He wrinkled his nose up in apology and flashed another dazzling grin at Rose, who giggled.

"I'm sure I'll get used to it."

"I'm sure you will. Now, where was I … ah yes. Regeneration. Well, like I said, sometimes I keep the same characteristics, sometimes I don't. It's sort of … pot luck, really. I seem to be recycling a lot of my fourth self – the jelly babies, the hopping –"

"Yeah, what was with that?"

"I'm not entirely certain. It was either the surplus energy lingering in my nervous system, a memory of a previous adventure or a leftover from my fourth self. After I regenerated into him I did a lot of skipping. Mind you, I was a good three hundred years younger then, I had a bit more energy back then." He paused. "Do you remember hopping for your life?"

"Yeah. You never explained exactly why we had to hop for our lives, though. Why couldn't we run? Why did we have to hop?"

"We didn't. I just thought it'd be fun to hop for a change. We always run."

He ate another jelly baby as Rose pressed on with her questions.

"So … what were your other selves like? I mean, before you regenerated."

"Why d'you wanna know?"

"Just curious, that's all. 'S'not every day your best mate has a complete image overhaul in the very literal sense."

"Fair point. Well, settle yourself down and I'll fill you in on the basics. Just lemme go and get the photos."

"Photos?"

"Photos," repeated the Doctor. "You didn't think I'd become nine hundred years old without taking a few shots for the family album, did you?" Rose and the Doctor grinned at each other as he bounded out of the room to get his photographs. After a few minutes, he returned with a large, leather-bound photo album, which he threw at Rose.

"There you go," he said. "Sit yourself down and have a flick through that. They're all labelled, so it shouldn't be too difficult to find the different me's." Rose jumped into the nearby armchair while the Doctor finally took his coat off, hung it up on the hook and loosened his tie before collapsing onto the recliner opposite Rose. The lounge area of the TARDIS was small but cosy, full of squashy chairs and comfy sofas, and it made for perfect conversation space. Ruffling his hair again, the Doctor settled himself into the chair and began to fill Rose in, while she flipped through the photo album.

"My first self – pre-regeneration, if you like – was a grumpy old git of four hundred and fifty years old." Rose quickly found a picture near the front of the album – a tall, skinny man with long white hair staring intently back at her with an unreadable expression on his pinched face. "I'd brought my grand-daughter here to show her the Earth – "

"Wait, hold on a sec," Rose said, looking up. "You never mentioned a grand-daughter before."

"Didn't have the chance." His voice became slightly quieter and his eyes momentarily lost their twinkle. "Susan. My grand-daughter. I loved her, but she thought I needed her too much. She fell in love, but refused to follow her heart, so I had to make her decision for her. I had no choice."

"What happened?"

"I locked her out of the TARDIS one day and never went back for her." The Doctor sighed and swallowed a lump that was threatening to fight its way up. "I don't know where she is and I probably never will. Anyway, even if I did see her again, she wouldn't recognise me. Not like this." After a moment's pause, his face cleared and he carried on at his normal excited pace.

"My first regeneration was interesting to say the least. I mean, it was my first one, so I didn't know what to expect. I changed into a bloke with a penchant for big hats and flutes, and when I first saw my new face … it was like my mind went into overdrive. I started talking about myself in the third person. Most unsettling."

Rose found a photo labelled 'Two', and found herself looking at a man with a craggy face and dark hair in a pudding-bowl cut. He was frowning intently at the camera as if wondering why whoever was behind the lens was bothering to take a photograph of him when he clearly had more important things to do.

"Regeneration number two was almost as bad as this one. I spent several days in one of your human hospitals – the number of tests they subjected me to, you wouldn't believe – but I got over it eventually. The clothes were amazing – cloaks, frilly collars, that sort of thing. Very dandy."

'Three' was exactly as the Doctor had described him – out side shot of Three showed him wearing a long, velvety-looking cloak and a frilly cravat. Three reminded her very much of an aging Austin Powers, without the glasses and bad teeth and with slightly fluffier hair. She smiled to herself.

"Can't really imagine you in anything else apart from leather, pinstripe or pyjamas …"

"Regeneration number three," the Doctor continued, pretending not to have heard her, "was one of my favourites. My fourth self – the one addicted to jelly babies – had an atrocious dress sense, but aside from that everything went fine."

'Four' appeared to Rose to be the most insane-looking, even by the new Doctor's standards. Staring wildly at the camera with wide, goggling eyes and a slightly open mouth, in the photo she had he was still wearing Three's outfit. Clearly, he had only just regenerated.

"Worse than the Austin Powers look?"

"Worse. Think trilby hat, that coat over there and a 20-foot-long stripey scarf."

"Bloody hell."

"Exactly. Can't quite remember what made me think it was a good idea, but I loved it at the time. Anyway, how many was that? Oh yeah, fourth. Right. So, my fifth self was a little less … adventurous, shall we say, than my previous incarnations. I couldn't decide on my own identity so I kept trying to do impressions of my former selves. Don't ask me to do that now, I don't think I could cope with nine impressions in one night."

Rose scanned the photos of Four, suppressing the urge to giggle several times when she saw him wearing the aforementioned scarf and trying to picture the new Doctor wearing such a scarf. Turning the page, she found photos of 'Five' – a young, blond Doctor in cricket whites looking at the camera with a rather sad and confused expression on his face.

"Why is your body getting younger as you get older?"

"No idea," the Doctor shrugged. "Perhaps it's part of the genetic make-up of Time Lords which prevents them from being afflicted with all the usual ailments that old people suffer from. Perhaps it's just fluke." He chewed another jelly baby thoughtfully before adding, "I hope it's the latter." Rose giggled as he ploughed on with his lifestory.

"Regeneration number five into self number six was one of the worst. The regeneration itself nearly killed me, and the after-effects nearly killed one of my companions."

"Really? What happened?"

"I'm still a bit hazy on the details … post-regenerative trauma, y'know … but one of my assistants, Peri … well, she got on the wrong side of my sixth self and I almost throttled her. Literally. Had her up against the wall and everything. Terrified her, terrified me … each regeneration is always more taxing to the body than the previous, and I just … I dunno, I just sort of lost control, I s'pose."

"You're not … I mean, you're OK now, right?" The Doctor chuckled.

"Don't worry, I'm not going to wake up one morning with a sudden desire to strangle you to death. Maybe your mother, or Mickey… or possibly that stupid Van Statten bloke, if we ever bump into him again … but not you. I've managed to control myself so far and I'm pretty certain I can carry on doing that."

The photograph of 'Six' surprised Rose. Not only was his outfit lurid and loud, but he looked surprisingly similar to Five in that he was youngish and blond, although Six's hair was curly and his eyes were slightly colder.

"Next came regeneration number six, a decidedly dull one, if you ask me … aside from the ridiculous clothes and that stupid cane, I wasn't really that different to my previous self. I was slightly shorter and I had darker hair, but aside from that I was pretty similar."

'Seven' was a slightly older, slightly plumper man, with prominent facial features and a slight double chin. His dark brown hair was flecked with grey, and his bowler hat and cane gave him the appearance of an extra from a Buster Keaton film. Rose thought he looked like a friendly sort of man, much nicer than Six at any rate.

"The next regeneration was a bit of an accident – it's a long story, but I got shot down by gang leaders and I very nearly died for real. I was brought to another of your human hospitals where a surgeon killed me and shoved me in the morgue. The anaesthetic nearly stopped the regenerative process – I'd been 'dead' for so long that I'd completely lost my memory. I knew I had a penchant for opera and 19th century clothes, but aside from that I was clueless. Got my memory back eventually, though. All in a days work. Rediscover my identity, save the world from terror … everyday stuff."

Rose shot the Doctor an amused look before examining the photograph of 'Eight'. Eight was a tall, striking man with shoulder length wavy brown hair and piercingly blue eyes. Rose shuddered involuntarily – Eight had a look in his eyes that unsettled her and made her think that the Doctor's past wasn't as simple as he portrayed it.

"Then … then came the Time War. The last great Time War, between Daleks and Time Lords." Rose held her breath. She rarely heard the Doctor talk of the Time War, and she could see he was upset – he wouldn't look her in the eye, and his hair was slowly becoming flatter through a lack of him playing with it constantly. He sighed and continued in a hollow voice. "Everyone lost, you know that … except maybe I won. Cause I'm the last of the Time Lords now. I don't know where Susan is, and I only survived that Time War because my TARDIS, my beautiful TARDIS, transported me away while I was regenerating. Regeneration number eight became Doctor number nine … and then I met you."

He looked up and smiled.

"I met you and I told you to run. We both ran, away from Autons, away from Nanogenes, away from Daleks … away from the end of the world. We ran away and I changed. I should have told you about it earlier and I'm sorry, but … I didn't think it would happen as soon as it did."

"I s'pose that's partly my fault," Rose admitted quietly, but the Doctor shook his head vehemently and frowned.

"No, Rose. You mustn't think that. The regeneration was no-one's fault. It happened because it happened and now I'm here." Rose sighed and looked up. The Doctor – the new Doctor – smiled gently at her. "I'm still the Doctor, Rose. I always have been and I always will be. I might have changed, but underneath it all I'm still the same." Rose giggled as the Doctor realised what he'd said. "Hang on, that didn't make sense at all, did it? Oh, you know what I mean," he added half-despairingly as Rose collapsed into giggles. The Doctor shook his head exasperatedly and held out the paper bag with the jelly babies in.

"Jelly baby?" he offered. "Call if a peace offering."

"Peace offering for what?"

"Well, for me changing without telling you, and for me not being much use when the Sycorax came to play, and for—oh, just have a jelly baby, go on," he said. "You know you want to." He grinned widely as Rose rolled her eyes and stretched out her hand to take one. As she chewed it, the Doctor jumped up and rummaged around in a corner of the room. Curious, Rose tried to move her chair to see what he was doing, but every time she moved, he moved to block her view.

"Doctor … what ARE you doing?"

"Looking for some—ah HA! Found it!" Straightening up, he turned around and threw something large and heavy at Rose, who ducked it as it hit the back of her squashy armchair.

"What the hell is that?" Rose exclaimed loudly. "That could have killed me!"

"Oh, don't exaggerate," the Doctor said as he hastily re-did his tie and put his coat on. "Just hurry up and take my picture."

"Picture?"

"Yes, come on, hurry up!" he said impatiently. "We haven't got all day!" Only then did Rose notice that the large and heavy object thrown rather rudely at her was an old Polaroid camera. Puzzled, she picked it up and looked at it, turning it over in her hands.

"How does it work?"

"Just point it and click," he said, straightening his tie and ruffling his hair again. He positioned himself for a photograph, paused for a moment and then grinned widely. Rose laughed.

"Well, I don't want to look like those other miserable old gits in the album now, do I?" the Doctor said in a mock-affronted voice. Rose giggled some more and held the visor to her eyes.

"Say 'cheese'," she said.

"Red Leicester," he said, grinning as Rose giggled again and took the photo. As it whirred out of the camera, the Doctor walked towards her and looked over her shoulder to watch it develop. When it had finished developing, the Doctor inspected it more closely.

"It's still weird seeing myself with sideburns," he muttered, scratching them. "Sideburns and really big hair."

"Suits you," Rose said as she got a pen out of her pocket and wrote on the bottom of the photograph. The Doctor smiled appreciatively at her.

"D'you really think so?"

"Well, yeah," she admitted. "You need a bit of hair on you, it adds to the look." The Doctor frowned at her. "I mean, if you'd worn that suit and you'd been a skinhead, you'd look ridiculous. Hair suits you." As the Doctor tried to fathom this reasoning, Rose slid the newly developed photograph into the album after the last one of 'Nine' and handed it back to the Doctor.

"'Ten'," he read. He looked at her and grinned. "Imaginative."