Jack grinned as he stepped into the TARDIS. He froze when he saw the Doctor though. He'd obviously regenerated. The Doctor stood watching him, hands stuffed in his pockets. Jack took a few tentative steps up the ramp, before breaking into a run and throwing his arms round the Doctor hugging him tightly. The Doctor hugged him back.

"Hey, Jack," he said quietly, finding that there were tears in his eyes. This was the last remaining person who he could talk to about Rose and they would truly understand.

"Hey," Jack replied, just as softly.

A young dark skinned girl stood watching them awkwardly. When they finally broke apart the Doctor launched straight into introductions to brush over any tension that might be hanging in the air.

"Jack, this is Martha," the Doctor grinned manically. "Martha, this is Captain Jack Harkness. Whatever you do, do not let him talk you into bed."

"Oh ha ha," Jack stuck his tongue out at the Doctor. "Things have changed a lot since we last saw each other Doctor."

The Doctor being a Time Lord meant he had Time Lord-y powers and could sense that it had been a lot longer (A LOT LONGER) for Jack than it had for him.

"I guess we've got a lot of catching up to do," the Doctor said finally. "How about a holiday somewhere?"

Of course the minute the word holiday left the Doctor's mouth it was a cue for every Time Lord hunting alien trying to conquer the universe to try and track them down. They stopped off on a planet and ended up running for their lives.

When they could they grabbed snippets of conversation. Jack explained about his immortality, the Doctor explained exactly what had happened to Rose. Somehow through it all, they both realised that even though they were the same people inside, they had changed a lot outwardly. Jack had lost a lot of his flirty-ness and the Doctor was a lot bitterer towards the universe.

When they returned to the TARDIS much later Martha took her leave and went off to bed. She had obviously realised the Doctor and Jack had a lot to talk about still.

"So… can you get rid of it then?" Jack asked quietly.

The Doctor had been moving round the TARDIS console for some time now, adjusting things here and there, murmuring softly to the ship itself, stroking the occasional panel. He looked up at Jack when he spoke.

"The immortality?" The Doctor considered. "The whole thing with Abaddon? I think that might've been the reason for the immortality and the solution to it. I don't think you are immortal anymore."

A smile crept slowly up on Jack's face.

"Really?" He asked.

"I've been running tests since you said and I couldn't work it out, but then you mentioned the whole 'end-of-the-world' thing and it sorta made sense," he replied.

"Right," Jack nodded. He'd hoped reverting his immortality might have taken longer. He wanted an excuse to stay with the Doctor.

"Are you…" the Doctor paused. "I'm sorry we left you on Satellite Five. I did come back. But I thought you were dead, I didn't want to upset Rose."

"It's fine, Doctor," Jack assured him.

"I didn't want you to think-" the Doctor paused in his movements as he reached Jack who was leaning against the console. The Doctor pushed his glasses further up his nose. They were incredibly close and the heat was causing his specs to fog up. "I didn't want you to think you were any less important than Rose."

"I know," Jack whispered. "But we both loved her enough to know that she was the only one who had to leave that hell hole alive. We were just an added bonus."

"I miss her so much, Jack," the Doctor sighed. "I would've picked you up sooner but I didn't want you to think you were a rebound from her."

"Then what am I?" Jack asked curiously.

"Something entirely different," the Doctor said. Jack was too turned on by this new Doctor to do anything else but kiss him then.

It wouldn't end with sex. They both knew that would make things too complicated and even harder to say goodbye when the time came. That didn't stop them sleeping together though, curled up in the same bed.

When they woke the next morning (or at least it was according to the TARDIS who was still floating in the space time vortex) they stayed in the warm bed together for a long time.

"When you take me back, don't forget to visit will you?" Jack asked quietly.

"Course not," the Doctor replied. "Might even get the right century next time!"

"Doctor," Jack shook his head, lacing his fingers through the Doctor's.

"I won't, I promise," the Doctor said softly with a more genuine tone.

When Martha got up they were already in the console room, acting as if nothing had happened. Well, Martha hadn't seen them together first time round; it might be a bit hard for her to take, especially when the Doctor knew how much she loved him.

"You two are up early," she noted smiling.

"Thought we better get an early start!" The Doctor replied grinning manically. "We're off to Pathorn Twelve!"

Jack groaned.

"And he's had every being on that planet," the Doctor pointed a finger at Jack. "Twice."

Martha giggled.

"Ooh dear," she said.

"You just love torturing me don't you?" Jack said but he was smiling to show he didn't mean it.

"Yeah, I love it," the Doctor said locking his gaze with Jack's and putting a little more meaning behind that than he meant.