Author's Notes: This is something I've had in my head ever since seeing "Parting of the Ways", the season/series one finale of the 2005 version of Doctor Who. It moved me that much. There really isn't much more to be said.

Something was wrong, and it wasn't just Rose unconscious on the TARDIS floor. Lisa could feel it. Deep down, she sensed something was wrong. Her body didn't feel right, and that only meant one thing. She looked to the Doctor, about to question him, when Rose stirred.

"What 'appened?" she asked, sitting up a little.

The Doctor cast a brief glance her way. "Don't you remember?" he asked.

She sat up a little more. "It's like…" she began. "There was a singin'."

He grinned. "That's right. I sang a song and the Daleks ran away."

"Doctor…" Lisa said quietly, trying to catch his attention.

Rose pushed herself up, trying to stir her memory. "I was at 'ome…no I wasn't I was in the TARDIS and, uh, there was this light…"

Lisa was watching the Doctor closely, and his eyes traveled to his left hand, resting on the console. His veins glowed briefly with a golden light, the same light from the vortex he'd been imbued with earlier. A sinking feeling came over her; it was the link between them telling her the truth. Something was going to happen, something monumental, and neither of them had the power to stop it.

"And…I can't remember anythin' else."

The Doctor and Lisa shared a meaningful look before he turned his attention on Rose. "Rose Tyler." He chuckled and grinned. "I was gonna take you to so many places. Barcelona. Not the city Barcelona, the planet Barcelona. You'd love it. Fantastic place. They've got dogs with no noses." He laughed. "Imagine how many times a day you end up tellin' that joke and it's still funny."

"Then why can't we go?"

"Maybe you will," said the Doctor, "and maybe I will, but not like this."

Rose finally stood up. "You're not makin' sense."

Unfortunately, to Lisa, he was making perfect sense. He was dying, he was going to regenerate, and there was nothing she could do to keep it from happening.

"I might never make sense again," he said, trying to be flippant, "I might have two 'eads or no 'ead." He chuckled. "Imagine me with no 'ead. And don't say that's an improvement." The smile on his face faded. "But it's a bit dodgy, this process. You never know what you're gonna end up with."

He doubled over in pain as a pulse of golden light over took him. Even Lisa could feel it; she lost her balance and tried to regain it by leaning on the TARDIS console.

Rose attempted to go to him before Lisa could recover enough to. "Doctor!" she shouted.

"Stay away!" he ordered through pain.

"Doctor…" Lisa cried weakly, trying to lock out the sensations his impending regeneration was sending to her body.

Rose looked from Lisa to the Doctor and back again. "Tell me what's going on," she said quietly, frightened. She, of course, had no idea what was going on.

"I absorbed all the energy of the time vortex and no one's meant to do that." His smile turned into a grimace as he used every effort to hold back his regeneration. "Every cell in my body's dying."

Rose was incredulous. "Can't you do something?"

"Yeah," he replied. "I'm doin' it now. Time Lords have this little trick…it's sort of a way of cheatin' death. Except…it means I'm gonna change and I'm not gonna see you again. Not like this." He tried to smile, tried to laugh. "Not with this daft old face."

"No!" The cry came from Lisa, who had finally regained the ability to speak. Tears were falling down her cheeks and she struggled to keep her voice under control. "Doctor, I haven't had enough time with you yet…"

He didn't need the link to know that she wanted desperately to go to him, and she didn't need it, either, to know that he wanted desperately to collapse in her arms and take his regeneration like he'd done all the rest: lying down. But, he couldn't. It was taking all his strength and will to fight it back just long enough to explain to Rose so she wouldn't be confused and scared when he next looked at her with unfamiliar eyes. He had to be strong, for Rose's sake, and for Lisa's, too. She was his best friend, with him through practically all his adventures. She knew regeneration, but she was quite correct that this just wasn't fair. He didn't have enough time with her, either.

The Doctor glanced between the two of them in turn. "Before I go…"

Rose was near tears, now. "Don't say that," she said, her voice shaking.

"Rose, Lisa, before I go I just want to tell you both, you were fantastic." He smiled at them, and try as he might, he couldn't keep the quaver out of his voice. "Absolutely fantastic." The look and link between him and Lisa expressed more than those mere words could ever have, and he just wished that Rose could have an understanding like that of the way he felt about her, this ordinary human girl. "And you know what?" he said, using his last moments to make things all right for them. Grinning, he said, "So was I."

As Rose and Lisa returned his smile, as if telling him that it was okay, he let go, and let the regeneration overtake him. The golden light filled his body and his head and arms were thrown back. His body twisted and morphed, his once close-cropped hair growing longer and his stature shifting slightly.

When he next looked at them with his new brown eyes, he was not the man they'd known. He had become Doctor Number Ten. "Hallo," he said, his voice unlike what he'd previously sounded like, then paused, running his tongue over his teeth. "New teeth. That's weird." He looked away for a moment. "So, where was I?" His gaze returned to the two girls. "Oh, that's right! Barcelona!" He smiled as Lisa and Rose just regarded him with their mixed and frazzled emotions.

Time would tell what will happen next. In the TARDIS, it always does.

The End