Amy and Rory were in the TARDIS (probably snogging); the kids were downstairs talking, and Alan had started making arrangements, which might end up being unmade if Luke changed his mind. It was just the tin dog, the Zyloc, and the Time Lord in the attic.

The Doctor couldn't look at her face yet. He would; he needed to, or he'd never believe it. For now he stroked one of her hands in his own, talking aloud. "I can't look back. It hurts too much. I told Rose that, a long time ago, when she asked why I left you behind. She wouldn't have accepted the simple explanation, that the Time Lords called me back to Gallifrey. Time Lords don't age—not like humans. I was older when I was younger, though. "

K9 pressed his nose into the Doctor's hand. "Mistress Sarah Jane."

"Good dog." He scratched the metal ears. "I sent you to her because I thought she'd need some protection. But she did a good job defending the Earth all by herself, didn't she?"

"Affirmative."

He glanced at her face for a moment. Still smiling, still so full of life that he couldn't believe it. "You aged well. Harry would be foolish to call you old girl now. It must be all that running you did. "The sonic lipstick was still in her hand. "No, you wouldn't have let it go. It was more than a tool—it was something to remind you of me."

From force of habit, he pulled out his screwdriver and ran it over her body. "After all those close calls—Morbius and Eldred and Metebelis III, it's a tiny cluster of cells that killed you." He scowled. "Why didn't you tell me? I could have taken you somewhere to cure it. "

Mr. Smith made the Xylock equivalent of a cough. "Doctor—"

"Don't call me that!" He whirled around, knocking the stool over. "Not now."

"Sarah Jane left me a message for you."

The Doctor swallowed and adjusted his bow tie. "What is it?"

"I will play the recording in holographic form."

And Sarah Jane was standing there. Her skin was pale, with the veins standing out like Cybermat venom. "If you're watching this, it means I'm dead. I'm sorry I didn't let you know, but I didn't want to make you say goodbye again."

"Sarah," he murmured.

"You might be thinking of ways you could have saved me. You might be blaming K9 for not telling Luke." A holographic K9 rolled into view on the edge of the screen.

"But it's okay, Doctor. Everything has its time, and everything ends. Pain and loss define us just as much as happiness or love—I told you this before."

The words squeeze his hearts. "I know." Rassilon, how he knew.

"I don't need to ask you to look after Luke and Sky; I know you will. Especially Sky—she's so young. But bring them back to see the others on occasion, please?" She stopped speaking and took a deep breath.

"You told me I was important. No one ever tells you that, do they? Well, I will. You're important, you're brilliant." He can see a tear on the hologram's cheek. "You're my Doctor, and I will always be your Sarah Jane."