"C'mon! Hurry up, you two!"

Rory Williams managed to glare at the offending individual leading the way along the corridor, but that was all. Even his wife, Amy, seemed to have no breath left with which to talk, and for her that was a true rarity. Not that he would have said that to her face. Ever.

"Bloody slow down, would you?" he managed to gasp finally. "You said you'd put all the pirates to sleep. What's the rush?"

The Doctor looked more than a little put-out, but slowed down regardless, much to the relief of his companions.

"But I like running. It's exhilarating. Isn't it?"

Amy snorted.

"Yeah, when we're being chased by Daleks or whatever, and if we stop running we're dead. Now? Not so much."

"Fine, then," the Doctor huffed. "We'll walk at a nice, leisurely pace. I'm sure the pirates won't wake up and come after us..."

"Oh, knock it off," Amy retorted. "What are you, ten? Don't make me have to tell River about this when we see her next."

That shut him up, quite effectively, thank you.

"Remind me again what we're doing here?" Rory asked. He was starting to feel more than a little grumpy. Honestly, he didn't mind running around like a lunatic, if there was a point to it. Right now, there didn't seem to be a point.

"We're looking for someone," the Doctor told them. "Do you remember the village on Tangar? The one that had the problem with the space pirates?"

"I remember," Amy confirmed. "The pirates were going to take all the villagers to sell as slaves, but someone saved them."

"More specifically," the Doctor corrected, "someone traded themselves for the villagers. I promised the leader that I'd rescue that person and put an end to the pirates. I've already notified the Shadow Proclamation and the Judoon should be here any time now. We just need to find this mysterious saviour of children. All in all, a good day's..."

He came to such an abrupt halt that Amy and Rory both crashed into him.

"Oi!" Amy protested, but the Doctor appeared oblivious, his attention very firmly elsewhere.

"Oh no," he muttered. "No... No no no... Not here... It can't be you..."

"Doctor?" Amy asked. "What's wrong?"

Still he didn't answer, but instead shut his eyes and focused. Rory was about to try when the Doctor's eyes snapped open and he took off at a run. Exchanging weary looks, Amy and Rory took off after him.

They caught up with him at the entrance to a darkened room that they could not see into. The Doctor stood there in silence, displaying the sort of frightening intensity he'd shown in the past when he'd had enough of playing around with a deadly enemy.

"Doctor?" Amy asked again. "What's in there?"

"Not what," the Doctor said grimly. "Who."

He activated his sonic screwdriver, and the room suddenly flared bright with light.

"Oh my god," Amy whispered.

In the centre of the room, a man hung, suspended cruelly by chains around his wrists. He was naked, and his body was a testament to the abuse he must have suffered at the hands of the pirates.

"Rory, help me get him down," the Doctor said urgently, and Rory acquiesced without question.

"Who is he?" Amy asked softly as she watched her husband and her best friend lower the unfortunate man to the floor of the chamber.

"He's an old friend of mine," the Doctor answered. "His name is Jack, and he used to travel with me. Rory, over there, see that old leather wrist strap on the table?"

Rory looked, and grabbed the item in question.

"This? What is it?"

"It's the thing that's going to get us back to the TARDIS, if I can get it working again. Hard to believe it was actually left here. They can't possibly have known what it was. Either that, or they were using it to taunt him."

Rory and Amy watched breathlessly as the Doctor worked. He was still working at it when they all heard the unmistakable thump of heavy footfalls nearby.

"Pirates?" Rory wondered in a low, anxious whisper.

"No, Judoon," the Doctor muttered. "Got to hurry. If they find Jack here, they'll arrest him on sight."

"But why?" Amy asked. "He's a victim here, isn't he?"

"Not because of what he has or hasn't done, but because of what he is. I'll explain later. Right now, we need to get him back to the TARDIS, where he'll be safe." A moment later, his face lit up. "Ah ha!"

"That sounds promising," Rory said with a touch of hope. The Doctor grinned maniacally.

"Both of you, put your hands on the wrist strap." He shuffled a bit, and pulled Jack's limp form into his arms before laying his own hand on the strap and activating it.

"Bloody hell," Rory moaned as they all collapsed in a heap on the floor of the TARDIS. "What was that?"

"Vortex manipulator," the Doctor answered. "Time travel and teleportation without the benefit of a space ship."

"Now I think I know what apparating feels like," Amy groaned.

Another moan caught their attention, but it didn't come from the Doctor, or Rory.

"Jack?" the Doctor asked softly as he continued to cradle the immortal man in his arms. "Can you hear me, old friend?"

Jack coughed weakly, and his eyes flickered open.

"Who are you calling old?"

The Doctor smiled fondly.

"Well, you have outstripped me in years. How old are you now?"

Another cough, and this time blood trickled from a corner of Jack's mouth.

"Lost count some time after three thousand. Doctor...? Where are we?"

The affectionate smile on the Doctor's face faded a little.

"We're safe in the TARDIS, Jack."

"Oh. Thought I heard her voice, but she sounds different. So do you, come to think of it."

A chill swept down through the Doctor.

"You can't see, can you?"

Jack tries to smile, but it came out as more of a bloodied grimace.

"Not a thing. Haven't been able to see for, oh, at least a couple of months now. I gave them the slip a few too many times. I don't think they liked it."

"The pirates, you mean?"

"No, the ones that the pirates are working for."

Jack coughed again, and again blood spilt from his mouth.

"All right," the Doctor murmured. "Enough talk. Rory, help me carry him to the med room."

Minutes later, Amy found herself the designated comforter while Rory and the Doctor dashed around, doing what they could for the injured man.

"I'm Amy Pond," she introduced herself, taking the liberty of clasping Jack's hand lightly in hers so that he needn't be confused about where she was. "Apparently the latest in a rather long line of travelling companions."

Jack half-laughed, half-coughed.

"Don't be offended. He's very picky about who he travels with. Trust me, I speak from experience. I nearly got jettisoned into the vortex at least half a dozen times before he finally accepted me."

"So you did travel with him, then?"

"Oh, yeah. It wasn't for long, but it was brilliant."

Amy smiled fondly.

"I know."

"What about the other guy with the sexy voice? Who is he?"

Amy smirked, both at Jack's unapologetic brashness and at the deep blush that spread across Rory's cheeks.

"That's Rory, my husband."

If anything, Jack actually managed to look turned on by that piece of news.

"You're taking on husband and wife pairs now, Doctor? Kinky."

"What can I say?" the Doctor replied with a cheeky grin. "I like a challenge."

Jack, who had fully expected some sort of reprimand, gave a blinding grin.

"Oh, I think I'm gonna like this regeneration."

"All right, Captain," the Doctor said lightly, though Jack could almost hear the smile in his voice. "You need to rest."

"There's a quicker way for me to heal," Jack suggested lightly.

"Not an acceptable option," the Doctor admonished him. "You'll have all the time you need to heal right here on the TARDIS. When you've had time to rest, you can tell us who it was who was in charge of the pirates."

"It was the Chulans," Jack answered tiredly as the Doctor, Amy and Rory all went to leave. "Specifically, one of the lesser royal families."

The Doctor stared back at Jack with a frown.

"Why would a Chulan Royal family want to do this to you?"

A bitter smile touched Jack's lips.

"Let's just say that old sins finally caught up with me."

The Doctor had a niggling feeling he should understand what Jack was talking about, but it so far eluded him. With a last murmured instruction to rest, the Doctor left Jack alone in the TARDIS' med bay.

"I've never seen injuries like that," Rory said later, when he and Amy sat in the kitchen with a rapidly cooling pot of tea between them. "I mean, I saw people badly hurt, but that was mostly from car accidents, and the like. I've never seen anyone hurt like he's been hurt, and it be from someone having done it deliberately."

"I know," Amy murmured. "I can't imagine what it must have been like, to be tortured like that. I don't even want to try. And the way the Doctor reacted... It was like there was something between them, like the Doctor thought he owed him for some reason."

"I do owe him."

Rory and Amy looked up questioningly as the Doctor joined them.

"How do you mean?" Amy asked. The Doctor watched them with a sombre expression that looked wrong on his too-young face.

"I've explained to you both about regeneration."

It wasn't a question, and they responded only with silent nods.

"Okay. I first met Jack in my eighth regeneration. He was running a con in World War II London, at the height of the Blitz. The silly fool nearly wiped out humanity with his stupidity, but he surprised me and that is not easy to do. There were a couple of moments when he could have run and left me and Rose to who knows what fate, but he didn't. Even when it could have cost him his life, he didn't run away and loved him for that. I took him on-board, and he proved himself again and again... So many times over, right up until Satellite Five."

"And what happened on Satellite Five?" Rory prompted.

"Captain Jack Harkness died, facing down a squad of Daleks."

"Well," Amy said with a soft huff of surprise, "he's looking pretty good for a dead bloke."

"How's he alive, then, if he died?" Rory asked. "Or did we somehow pick up a version of him from before that happened?"

"If we had, he wouldn't have known me at all," the Doctor said. "No, what happened to Jack was impossible. Rose... my other companion at the time... opened up the heart of the TARDIS. She absorbed the power of the time vortex and she brought Jack back to life." The Doctor smiled sadly and shook his head. "All that power, and her thoughts were still for everyone else. The only problem was that she gave him too much. In her desire to save Jack, she made him a fixed point in time and space."

"What's that?" Amy asked. "What does it mean?"

"It means he never changes," Rory answered before the Doctor could. "He'll never change, never get old, never die. He's immortal, isn't he?"

"As close to immortal as any creature in this universe could hope to be," the Doctor confirmed. "You're close, but not exactly right. He will age, albeit very slowly. He does die, but the vortex brings him back to life every time, no matter how death occurs, and he will die for good one day, but that will be a long time into his personal future."

"You've seen it, haven't you?" Rory asked. "His final death? You've seen him die for the last time."

"Yes, but you can't tell him that." The Doctor paused and then added ruefully, "Spoilers."

"It's not as fantastic as it sounds, is it?" Amy said. "Living for so long?"

"No," the Doctor agreed. "It's not, and I can't undo it. Jack will live on, for far longer than any living being in this universe. Even me."

"Doctor," Rory said tentatively, "these Chulans... How likely is it that they'll be willing to just let Jack go? Assuming they know he can't die?"

The Doctor's expression told them the answer to that question well before he actually spoke aloud.

"They're an unforgiving race. If Jack has wronged one of them, they will never give up hunting for him. Especially if they know about his immortality. Oh, Jack, what did you do?"

to be continued...