She didn't sleep at all that night, and he slept only fitfully, still murmuring Rose's name every so often. She winced every time she heard him calling for the woman he loved, the woman who had the whole of his heart. Her thoughts kept spinning. She wanted to leave. She had to leave the Tardis, and Jack and the Doctor. She was too hopelessly in love, and there would be no peace while he did not love her. But…

"I promised to stay." She murmured. It had been a foolish promise, made to a man who'd thought she was someone else, but she'd made a covenant with the man she loved, and she'd never break it. No matter how much it hurt.

"Did you sleep much?" he asked, and she turned. His eyes were wide open and he was staring at her. She wandered how long he'd been watching her.

"Not at all." She admitted. He got up, and swung his legs over the side of the bed.

"I feel rather tired." He told her. "I don't think I slept at all well."

"You had nightmares." She said, in a small, quiet voice. "You were calling out in your sleep."

"Really? Who was I calling for?"

She watched him for a moment. Now she should tell him. Tell him he called for Rose, and still loved Rose, and she loved him too much and he had to take her back home, please.

But she had made a promise.

"I don't know, I couldn't understand you." She lied. He stared at her for a moment, with that look that made her feel like he could see right down into the very heart of her soul, then walked over to the door.

"No, no way through that lock." He announced cheerily. "We'll have to sit around and chat until the guards come and we can make our daring escape. So," he said, sitting on the edge of the bed, "what do you want to talk about?"

She didn't know what she was going to say until she said it.

"Rose."

"Ah." He said. "Rose." He looked away from her, over into the distance, into memory. "I loved Rose."

He glanced back to the woman opposite him huddled miserably into a corner. He liked her. He'd always liked her. She was funny, and clever and resourceful, and brave, and she amused him, and fascinated him, like all his companions did. And he'd seen the look in her eyes, like he had seen in so many companions eyes, and carefully and scrupulously ignored it, because he could not return it.

But he had loved Rose. He still did. And he knew that he had called out Rose's name last night, and now this woman by his side knew what he was capable of, knew what he held back from her. Knew what Rose had finally taught him to do.

He'd wanted to be alone after Rose. But he couldn't be. The Tardis was too big. Too full of old memories, of lost companions and evil enemies and terrifying monsters. Alone he could hear voices, just whispers on the air, Ian and Barbara whispering to one another, a faint waft of Victoria's perfume, an echo of Adric's last words, Jo's last goodbye. Too many memories, piled on top of him, one by one, all those dead friends and enemies, until he almost suffocated. No wonder the Time Lords chose to live in solitude most of the time. An almost-eternal life created too much past, much of it painful as loved ones died. No, he couldn't be alone, so another companion had to be found, and he picked up the first human who wanted to leave that he found. And he had held back from her, as he had tried to hold back from Rose.

Rose had his heart. That was still true. But Rose had gone. And somewhere, in his fevered dreams last night, he remembered this woman, his new companion promising to never leave him.

And she had meant it. He would never be alone again. And that was a precious gift, that deserved far more from him than he had been willing to give.

He had said his final goodbye to Rose, in life, and in the last night's dream.

"Did I ever tell you," he said slowly, "that I have two hearts?"