Rose rested her head on his chest and listened to the beating of his hearts, a smile on her lips. He stroked her hair absently and they rested content in each other's arms, like coming home after a very long trip.

"So," said Rose softly into the quiet room, "enough about me. What've you been up to?"

"Saving planets, annoying governments, running for my life. The usual," he said with not a trace of humility.

"Still with the running?"

"Always," he grinned. "You know you liked it."

She huffed a short laugh. "Yeah. I did. Have you been travelling… with anyone?" Rose asked carefully.

He shook his head, an inscrutable expression across his fine features. "No. Just me."

"You shouldn't travel alone. What about Donna? She was brilliant. I liked her."

His face fell, "He never told you, did he? He'd have known what would happen." Rose shook her head. "The metacrisis was dangerous for her. She still has a human brain, she couldn't keep a Time Lord consciousness in there. It would have burnt her to death. Like you with the Time Vortex. I had to lock away her memories. Everything to do with me, and she can never remember again."

Rose could hear the despair in his voice. John had referred to Donna as his best mate, and Rose knew the woman was special to him beyond measure, in a different way from Rose but no less. "I'm sorry," she said sadly. He squeezed her hand back, grateful for the contact.

He gave her a sad smile, an expression she returned, and met her eyes in a long look. It had been three years, for him, since they had had the opportunity for such contact. The last time he had seen her, it had been only a matter of hours they had spent together. It was not what he would term quality time, what with the Daleks, impending end of the universe, and the fact that he was duplicated in those few hours. Not much opportunity to relax together.

"What are you thinking?" she asked gently. "I can see wheels turning."

"Just remembering the last time we were together like this." He put his arms around her shoulder and she adjusted herself against his side, leaning her head against his shoulder.

"Ghostbusters," she remembered with a giggle. He began to hum the recognizable theme and Rose laughed heartily. "Oh God that was forever ago."

"You were so young then," the Doctor said wistfully, then his eyes went wide. "Not that I'm calling you old. Not at all. Definitely not calling you old. Nope."

Rose chuckled to herself and swatted his chest playfully with an open hand. "I know what you meant, you idiot."

"What are you going to do now?" the Doctor asked, unsure what he wanted to hear in response. He didn't dare hope, but at the same time he reminded himself that he did not have long himself.

"I don't know," Rose said honestly, shrugging. "We'd never really thought past getting here and finding you. Too afraid to dream, I guess. Or I just couldn't accept that it could be possible. But here we are and I have absolutely no idea what to do next."

"You're dead, officially, back on Earth, but I'm sure you could undo that without too much work and get some paperwork for Tony. Jack could probably fix you up easy enough. He has all sorts of contacts, not that I want to think about why he knows so many people so well."

Rose giggled at the memory of the flirtatious reformed conman. "And go back to do what? Work in a shop? I don't even have my A levels here," she groaned at the thought. The better part of a decade in academic research and all her publications were in the wrong universe. "I don't know, I really don't. Tony needs some sort of stability, I think. He's a good kid, but he's never had the chance to be a normal child."

"He isn't, though, is he?" the Doctor asked in an odd voice. Rose looked at him enquiringly. "Normal. Human normal."

"No, he's not," she said quietly. "He's a right genius."

"He is," the man said. "Looked right into the Untempered Schism and came away from it with a headache."

Rose winced at the far too recent memory, the terror she'd felt on seeing him frozen in place before the swirling, violet gap in reality was still raw on her nerves. Anxiety bloomed within her chest as she deduced where this conversation was going and she braced herself.

"Rose, human children can't do that," said the Doctor quietly.

She sighed and closed her eyes a moment. "I know." Her voice was very soft in the large room.

He swallowed heavily and placed a hand at her chin, turning her face to look directly at him as he spoke. "Rose…" He drew in a deep breath. "Who are Tony's parents?"

"According to his birth certificate, Jacqueline and Peter Tyler."

"And according to his genes?" His hearts pounded in his chest, beating out a staccato note against the quiet that stretched too long.

Her eyes burned into his, all the answer he would need laid raw before him in her gaze. "Does it need saying?" She turned his own words of years before back on him.

Wordlessly, he rose from the jump seat and strode towards the corridor, his long legs carrying him quickly, his expression blank. It took him only a few seconds to find the worn, oak door that marked Rose's old bedroom. He pushed the door open a crack and peered in at the sleeping child.

Beneath the soft yellow duvet, Tony rested peacefully. Every few moments, he muttered quietly to himself, but his breaths were deep and steady, unoppressed by the weight of grief that had led him to cry himself to sleep. His pale blonde hair stuck up in many directions, twisted and mussed by the pillow.

The boy's eyes flickered beneath his eyelids as he dreamed. The Doctor stepped into the room as quietly as he could and gently placed a long-fingered hand on Tony's chest where it rose and fell steadily. Beneath his fingers and through the worn cotton of the sleeping child's shirt, he felt the unmistakable gallop of two hearts.

He didn't hear Rose come up behind him, but felt her hand on his shoulder. He turned to face her, a look of infinite tenderness and awe across his features. She put a finger to her lips and left the room quietly, leading him to the library. They walked silently toward the well-loved sanctuary of books where they had holed themselves up for so many days over their years together. The Doctor's mind was a torrent of thoughts whirling about, one chasing the other and none staying long enough to fully consider.

Rose sat down in her favourite soft, leather chair near the cold fireplace. He sat down opposite her, in his own matching chair. Rose pulled her knees up to her chest in a gesture he had seen her do a thousand times. She drew into herself when she was nervous.

Finally, after a moment staring off into nothing, she spoke. "He was born May twenty-sixth, two thousand and seven. It was eight months after we were separated, by that universe's calendar anyway. I don't know when it was for you. I was three months gone when you said goodbye that November."

"Why…" he croaked. "Why didn't you tell me?"

"I was going to. When I mentioned the baby and you looked so happy and hopeful for just a second…" she returned, her eyes shadowed. "You had lost your world and your family already, and you told me travel between worlds was impossible. I just couldn't make it worse by telling you that you were going to lose someone else too." She shook her head sadly.

He drew his lips into a fine line. "Did John know?"

"He knew," Rose confirmed with a nod. "It was our first big fight when he found out since I didn't tell him right away. He loved Tony very much, and Tony loved him. They were inseparable whenever he spent time with us, which was a lot. Almost every weekend until John got really sick."

"Have you told Tony?" His voice was low and dark in the otherwise silent room.

She sighed. "I meant to. John wrote him this notebook like he did for me and I was supposed to give it to him for his tenth birthday, but I didn't."

"Why not?" his voice was laced with a quiet anger that simmered just below the surface.

"He just lost the only parents he ever knew. How could I go tell him that they'd lied to him his whole life? It would destroy him to be told that these people he was grieving weren't even who he thought they were. He's really strong, Doctor. He is amazing, he really is. But he has been through a lot. He has lost everyone he ever knew except for me. He's only just in the last few weeks started letting himself be happy again." She met his eyes, imploring him to understand. "He is a little boy who has lost everything. I can't take the memory of his parents away from him now."

The Doctor watched Rose carefully. She had unfolded her legs and sat rigidly now, her calmness from earlier gone. Her expression was tense as he took in what she said.

He had felt the boy's presence from the moment he landed on the planet. The faint wisp of awareness that he had once sensed of all Gallifreyan children and Time Lords alike; that tickle in the back of his mind that told him where to find the person who had called for his help. It had shocked him when he had entered Rose's TARDIS only hours earlier and realized the feeling originated from the boy.

It had shocked the Time Lord to the core when Tony had turned to look at him and the Doctor had seen a child who could have been his mirror image nine hundred years prior. Pale blonde hair, bright blue eyes, even the freckles across his nose. Long and lean and wiry. The child even smelled of Gallifrey; of spiced air and ancient earth.

Rose's confirmation of what he already knew in his hearts to be true left him reeling.

This woman, this incredible woman, had not only torn through universes to find him – twice – she had restored his planet and brought him a son. He was not the last of his species any longer; there would be another, a son he could bring up to do the good he himself had always never quite managed. He felt the subtle poison of hope start to flow from his hearts but immediately ground it to dust.

This was a child with no idea of who he truly was which, perhaps, was for the best. With the destruction the Doctor had wrought, and with an axe hanging over his neck, it wouldn't do to hurt the child when he died.

Her voice broke into his morbid thoughts, seeming as though she was uncomfortable with his prolonged silence. "I don't regret leaving him with mum and Pete, you know. He had a good life, a better life than I could give him running around fighting aliens between classes, and it was the safest place for him. Especially with Torchwood being what it was."

The Doctor shot a skeptical look at Rose. "How was he safe from Torchwood being raised as the son of its director?"

"Keep your friends close and your enemies closer," Rose said simply, with a shrug. "There was no one, absolutely no one, in a better position to be able to keep Torchwood away from Tony than Pete. Every decision went through him, every mission, every investigation."

"Is that why they came after him?" the Doctor asked, connecting dots in his mind.

She nodded sadly, her eyes hooded with anger at the betrayal. "I don't know how much they knew about Tony, but they knew that Pete was keeping something from them. It's how they got the president involved. Accused him of being corrupt, of hiding dangerous information. We knew it was possible this would happen; it's why John and I prepared an exit plan and why Tony and I didn't hide out on Earth. If Torchwood really knew what Tony is…"

Rose looked up and could see the rage of the Oncoming Storm in his eyes, clearly having come to the same conclusion.

"How did he never figure it out? Tony is bright; surely he noticed having two hearts before now."

At this, Rose actually smirked a bit proudly. "Ever hear of situs inversus totalis?"

The Doctor flashed her an offended look. "Organs completely flipped around the midline. Rare anatomical malformation in humans."

She nodded. "Strange things like that happen naturally from time to time within every species. Some people are born without certain organs, or with duplication of others. Two heads, sometimes, or complete duplication of limbs. Wasn't that hard to come up with a convincing explanation for congenital complex dicardia. That's his official diagnosis, by the way." Rose looked at him steadily. "The only Time Lord he knew only had one heart and there were no others. Me, mum, and John were the only people alive in that entire universe who knew that Time Lords had two hearts. We just never told anyone else. Tony believes he has a unique medical condition, that's all."

The Doctor nodded. "That's… creative."

"He asked about it when he was five. Had to come up with something."

"And what will you come up withif he notices that I also have a binary circulatory system? I'm sure he's clever enough to draw some conclusions from that."

Rose inhaled at length and leaned back against the back of the chair. "Cross that bridge when I come to it, I guess. I do need to tell him eventually, and I'm not sure if it's better to wait for him to figure it out or tell him as soon as he's ready and get it over with, like ripping off a plaster. Too soon right now, though. Needs to wait until we're settled. Somewhere."

"What do you want to do, Rose?" the Doctor said quietly into the heavy air between them. He stood and began to pace. "Do you want to go back to Earth? I can take you both to Earth, and help you get settled there. Get Tony into school, get you a house. Maybe not the Powell Estate, eh? Think Tony'd like the Dragon School? Good name that, Dragon School. Bit Harry Potter. You went to Oxford, you'd know the city."

She watched him carefully, seeing the way he'd shut himself off suddenly. Rose recognised his tendency towards avoidance. When he was uncomfortable, suddenly something else seemed very pressing. It was his way, but right now it was the absolute last thing Rose wanted to see him do. She couldn't help the hurt that settled in her at the thought that he would be so ready to see them off so soon after finding them.

"Can we stay with you?" Rose asked in a small voice. "At least for a while, if that's okay. Today was a very long day, and I can't really come up with a plan worth anything right now. I just need to collect my thoughts for a bit. I -" She broke off, letting out the remainder of what she had to say as a breath and gave him a half smile.

"That would be brilliant," he said happily, the tension unwinding from about his shoulders and his demeanour brightening instantly. He flashed her that grin, that all-teeth, face-cracking smile that was completely adorable and also made it hard to remember that he was nine hundred years old and one of the most dangerous and powerful beings alive. Rose loved that smile, and she had missed it like the earth misses the sun at night, and she couldn't help her own grin in response as he went on. "I'd love for you to stay. Both of you. As long as you like."

A/N: Situs inversus is a real anatomical malformation. It's really quite cool to see on a radiograph or MRI.

Complex congenital dicardia is completely made up, though. I did do a rough anatomical sketch of just how that binary circulation might work from a physiological point of view.