Disclaimer: I don't own anything in the Who-verse. That honour belongs to RTD and the mighty and glorious BBC. The only thing I get out of this is a warm fuzzy feeling knowing I am trying to put right what once was wrong.

Author's Note: So here we are, the penultimate chapter. Apologies to everyone at the length of time it has taken to post this. Annoying Christmas jobs and a continuing poorly daughter (now thankfully on the mend) have been doing their best to keep me occupied. Lots of questions answered...

BTW, big thanks and hugs must go to Marzi for prompting me to rewrite Jack's reaction to the Doctor's arrival. It just felt so right!

Chapter XXII

By the time Jack reached the TARDIS the wooden doors were already open although the Doctor was nowhere to be seen. Curious Jack poked his head through the open door to look inside. Still no Doctor. There was a clunk somewhere behind him, telling him that someone had accessed one of the big metal blast doors that separated the main Hub from the lower levels. Jack spun round and set off in the direction of the sound. Clearly the Doctor had already embarked on his usual exploration session. Jack wondered how he'd managed to get past him without being seen. From the moment the TARDIS had begun to materialise right up to the moment he'd poked his head through the door the only time the TARDIS had been out of his sight was when he'd turned to descend the second of the two flights of stairs which led up to his office and bedroom. It had taken him two seconds to make the turn, hardly enough time to sneak out of the TARDIS, certainly not enough time if it had been accidental. No, the Doctor wanted to find something in the lower levels of the Hub before he saw Jack. There was only one thing Jack could think of that would spark the Doctor's interest down there. With a muted curse he sprinted towards the vault.

The door to the vault was locked. Jack recognised the signature of the Doctor's sonic screwdriver and, after trying to yank open the door unsuccessfully half a dozen times, he gave up and resorted to braying on the door with his fists.

"Doctor," he yelled furiously. "Open this door now!" There was silence from within. Jack was scared. What was the Doctor up to? What reason could he possibly have for accessing Ianto's body? Jack's fear made his voice climb in pitch, yelling for the Doctor over and over. But still there was no response from inside the locked vault. Finally with a sob of fear and frustration combined, Jack allowed his legs to collapse beneath him and he leant with his back against the door, half-heartedly striking the metal with his clenched fist.

He must have been sat there a good ten minutes, the only sound being the dull repetitive thud of his hand on the door when there was a lock click and the heavy metal door swung inwards, dumping him unceremoniously at the Doctor's feet. The Doctor looked at him in surprise and offered his hand down to help Jack to his feet. Jack brushed the hand angrily away and clambered to his feet unaided. Then without a pause he pulled back his fist and let fly, all his frustration concentrated into those five fingers. There was a dull satisfying thwack as he connected with the Doctor's cheek, sending the Time Lord sprawling in a heap on the floor.

"I asked you to let me in." Jack's voice was cold and unforgiving.

The Doctor looked up at Jack from his position on the floor somewhat dazed, and rubbed his now reddening cheek.

"I suppose I deserved that," he muttered, clambering to his feet, as it became obvious Jack was not going to offer him a hand. "Didn't think you'd actually do it though. It hurt you know."

Jack ignored him. "I asked you to let me in," he repeated.

"I was busy," the Doctor replied bluntly, his voice flat. "I'm surprised you didn't wake the whole of Cardiff with that racket. I'm sure you woke Siân up. Shouldn't you go check on her?" It was clear that he seemed eager to change the subject.

"I will in a minute," Jack said silkily. "After you tell me what you were doing in the vault." He knew he should be surprised that the Doctor knew of Siân's presence in the Hub but he wasn't, and besides at that moment it didn't matter.

"I was checking," the Doctor said, seemingly unwilling to elaborate.

"Checking what?" Jack voice was more low and dangerous than the Doctor could ever remember.

"I was checking the condition of Ianto's body actually. Checking that the cryopreservation was intact."

Jack's face blanched.

"Why? Why would you do that?"

The Doctor looked at Jack for almost a minute before replying.

"To see if he can be revived. Ianto isn't dead."

The Doctor watched as the last vestiges of colour drained from Jack's face. Concerned that he might be about to pass out he put his arm out to support him but Jack pulled away sharply unable to bear his touch.

"That's not funny," he flared.

"I wasn't trying to be," the Doctor replied kindly. "I meant it. He's not dead."

"I don't believe you. I felt him die," Jack protested, "He died in my arms. I died. After the 456 were destroyed I sat with him for five days. I think there might have been some kind of sign if he were alive don't you?" The Doctor matched Jack's disbelieving gaze steadily. Clearly Jack was not prepared to take this on trust.

"It's complicated," he said slowly. "There's a lot I need to tell you."

"If Ianto really is alive then you can explain after we revive him," Jack said, turning briskly and lunging for the drawer containing Ianto's body.

"No!" the Doctor said sharply putting his hand out to restrain him. Despite his lanky stature he was surprisingly strong and held Jack back with apparent ease. "You can't wake him yet. It's not as simple as that."

Jack's face fell. "Why did I just know you were going to say that?" he said bitterly, his disappointment evident.

"Experience?" the Doctor suggested with a slight smile.

"Bitter experience," Jack agreed with a distinct lack of smile.

"Look, it's not as if he's going anywhere," the Doctor reasoned thoughtlessly, earning himself a vicious glare from Jack. "What I mean is," he continued hurriedly aware that he was on precarious ground. "Nothing is going to happen in the length of time it takes me to explain, is it?" He was modestly reassured by Jack's curt nod of the head. "So can we go upstairs where it's warm. This is going to take a while and I could really murder a cup of tea."

Jack almost smiled. The Doctor's love of a good brew was legendary amongst those who had travelled with him. Some had even speculated that the reason the Doctor was so fond of Earth was that it was as he had put it 'the only place in the whole damn universe you can get a decent cup of tea'. His amusement was almost instantly replaced by a searing spurt of anger and instead he merely pushed the Doctor, none too gently, out of the vault into the corridor beyond. The Doctor, a relieved expression on his face, scurried in front of him trying to stay out of arms' reach. On reaching the main Hub Jack curtly pointed to his office and they both mounted the stairs not speaking. Jack propelled the Doctor through the office door into the dimly lit office space.

"Stay here," he ordered, returning to the corridor and shutting the door behind him. He continued along the gantry until he reached the room which he had commandeered as his living quarters and silently pushed open the door. Siân was still fast asleep, apparently unaware of the ructions which had taken place below. With a relieved sigh Jack gently pulled the door closed and returned to his office. In his absence the Doctor had made himself at home and was rifling through the papers on Jack's desk with unabashed curiosity.

"Oooh, you've got an MIP. I've always wanted a look at one of those. Have you managed to open it yet? I hear they can be quite tricky." Babbling away the Doctor appeared oblivious to the thunderous glower on Jack's face.

Thud! The Doctor suddenly found his head was plastered against the solid wood of the desk, the not inconsiderable weight of Jack Harkness pressing down on his ear.

"Huh...dugh...pwfff..." he spluttered, his mouth buried in the files that, mere seconds ago, had been the centre of his attention. Jack eased the pressure allowing the Doctor to manoeuvre his mouth free of the obstruction.

"Look, I know you're angry..." he started to say but was silenced by a growl from Jack. "OK, more than angry. Furious, incensed, enraged, irate, wrathful, livid...come on I'm running out of suitable adjectives here. Really really mad, will that do? And you deserve to be. But I can't explain with my head glued to a table..." There was a moment of increased pressure on his ear and then suddenly Jack was gone, stalking across the room scowling as if he were an animal cheated of his prey.

The Doctor slowly raised his head from the table rubbing feeling back into his ear, waiting for Jack to turn and face him.

"Well?" Jack's expression was terse and unforgiving. "Go on then. Explain. All of it. Ianto. Siân. From the beginning...Now!"

"The 456 was never supposed to happen," he said quickly. He saw Jack start but continued before he could interrupt. "Not in 2009, not in 1964. Originally the Earth never came to their attention..."

"So what changed? What did you do Doctor? What exactly did the 456 do to Ianto. If he isn't dead then what the hell happened to him because he fucking well isn't alive by any definition I know."

The Doctor flinched at the venom in Jack's tone. He knew Jack had every reason to be angry, he had played with his life in an unforgivable fashion. Even the knowledge that what he had done was for the good of every human being alive seemed poor justification. But the thought that Jack believed that the actions of the 456 were somehow his fault struck him to his very core. The truth was, in some respects, it was his fault. He had started a chain of events which had inexorably led them to this point, but he had been blind. He had once said to Rose, boasted almost, that he could see all of time, all that had ever been and all that would ever be. And that was true, to a point. The fixed points in time around which the whole of time and space revolved, those he could sense. But he hadn't foreseen the creation of the greatest fixed point in time of all, Jack Harkness. In the end all roads led back to Rose, his beloved Rose. The day he had taken her hand in his, felt the sudden connection that unbelievably spoke to him of home, that was the event which had altered the time lines so irrevocably to bring him, and Jack to this point. Without Rose, without the Bad Wolf, there would be no Jack Harkness, fixed point of Time; no Torchwood; the history of the Earth was changed forever. But even though he had set that train of events into motion, he wasn't prepared to take the blame for the 456. That lay firmly at the door of someone else.

"It wasn't me," he said calmly, trying not to sound as defensive as he felt. "It was Dalek Kahn." He saw some of the hostility leave Jack's eyes and was for some reason ridiculously comforted by it. "When he manipulated the time lines to bring Donna and me together. You know what happens as well as I do when you start interfering in the time lines Jack. It's like dropping a stone in a pond, it sends ripples out through space and time, the consequences of which are impossible to predict. The 456 was a consequence of one of those ripples. They are an old race, so old their name has been lost in the mists of time. They come from a region of the Universe which is practically uninhabited. In the original time lines the species died out before it had time to identify human children as a possible source of chemical stimuli. Something changed as a result of Dalek Kahn's interference and they found out about humans. And they came looking."

All the time the Doctor had been speaking he had watched as he saw a glimmer of hope dawn in Jack's face. He knew what his next words would be and he dreaded the effect his reply would inevitably have.

"If it was never meant to happen then surely we can go back and change it. Steven doesn't need to die? Ianto would still be...here."

"It doesn't work like that," he replied sadly. "Those events have become fixed in time. If we change them the time lines will unravel, into the past as well as into the future. There is no telling what damage we could do. The time lines created by Dalek Kahn all centred on Donna. If Donna never met me, imagine what could have happened. Apart from anything else she would never have met you. Siân wouldn't exist. I'm sorry Jack. If there was a way I could bring Steven and Ianto back I would, you know that."

He watched as Jack visibly deflated and, with the air of an old man, sink down onto the sofa where less than an hour before he had been laughing with his daughter.

"Why are you telling me this Doctor?" he said tiredly. "If I can't do anything about it. If I can't save them, what is the point?"

"Because it isn't over yet. Fifteen years from now the 456 come back. They attack without warning. They release the virus to decimate the adult population and take all the children. Every single child under the age of twelve vanishes without trace. Earth is crippled. The human race never recovers."

Jack paled. "You've seen this?"

He nodded. "Before I came looking for you on Earth in 2009, I visited Earth in the year 2059. It should have been one of the most exciting times in Earth history; the establishment of the first Mars colony. But there was nothing, Earth was practically a dead planet. That's when I came looking for you in Cardiff and learnt about the 456. I traced the time lines forwards and back, found the connection to Dalek Kahn, and identified the date the 456 attacks for the third and final time. At the moment it's not a fixed point in time, the time lines are in flux. We need to stop it happening or the whole future of the human race will cease to be."

"No pressure then?" Jack said wearily. "How do we stop it?"

"We don't, she does." the Doctor pointed to a framed photograph on the shelf behind Jack's desk. It was of Donna holding the newborn Siân.

Jack looked confused.

"Donna?" he said disbelievingly. "Is this the third time she saves Earth?" As much as he loved Donna he couldn't see how she would be able to defeat a race of aliens practically older than time, not without retrieving her buried memories anyway.

"Siân," the Doctor corrected, a hint of a smile crossing his features for the first time since they had come up from the vault.

Jack couldn't keep the incredulity from his face.

"But she's eight years old," he protested. Then a look of blind panic descended over his face.

"You're not sacrificing her to those monsters like I sacrificed Steven. I'm not losing another child to those bastards." His voice bordered on the hysterical.

"No!" the Doctor practically shouted his denial. "I promise you Jack, not one human, child or adult, will ever be harmed by the 456 again. You have my word."

"So how will Siân save the human race? I'm not putting her in any danger. I'm sorry. I'm not risking her, not even to save this whole goddam planet." Jack's voice was calm once more but implacable. Nothing the Doctor could say would ever change his mind on that score. Fortunately he didn't need to try. The Doctor gave him a sheepish smirk which immediately made Jack wary.

"You never asked me what Siân's doctorate was in," he said mildly. He paused for effect as though he were announcing the finalists of some reality talent show. "It was virology."

"Siân finds a cure for the virus?" Jack asked wonderingly, impressed at the complexity of the Doctor's machinations despite his continued anger at his entire family being manipulated at the Doctor's whim. The Doctor nodded proudly. Jack frowned. "Why does it need to be Siân? Couldn't you just whip one up here and now? It wouldn't be the first time," he questioned.

"Nope. In the first instance I'd be breaking the first rule of the Time Lords by directly interfering in the development of a civilisation." He caught Jack's mocking look and had the good grace to look abashed. "Well I realise it's more of a strong guideline than a strict rule as far as I'm concerned, but to be fair for the most part I try to stick to nudging..." He caught Jack's eye again. "Well prodding anyway... Secondly it's a seriously complex virus. Nothing like it has ever been seen in this part of the Universe before. Even for me it would take some time to crack. But Siân, she's special, she'll be able to try things I wouldn't even think of."

Jack looked puzzled. The Doctor grinned. He loved being able to surprise his companions, even ones as intelligent and well-travelled as Jack. He took a seat next to Jack on the sofa, considering he was probably safe from his wrath by now. Jack's eyebrows shot up, but he said nothing and shifted further up the seat to make room for the Doctor's sprawling frame.

"Do you remember when Donna became the Doctor-Donna?" the Doctor began. Jack returned a withering look which caused the Doctor to continue hurriedly, "She said there were things she could think of which I never could because I lacked that spark of what it was to be human. She called it gut instinct. And she was right. But Siân..."

"Has all of your intellect, but is also human..."

"The best of both worlds," the Doctor agreed happily. "All I needed to do was nudge her interests in the right direction."

"The microscope!" Jack interjected. "I always wondered what made you choose that as a present for a three year old."

"All you need to do now is recruit her into Torchwood after she finishes her doctorate and..."

"Whoa there, Doctor. There is no way I'm letting her get mixed up with this place. It's not safe! Just look at what happened to Tosh and Owen, not to mention Ianto." The Doctor heard his voice catch on the last name and inwardly smiled. Just a few more minutes and then he could finally tell Jack the truth about the fate of Ianto Jones. For the present he merely looked at Jack sceptically.

"Knowing your daughter, do you think you have any chance of stopping her from joining Torchwood. She's already managed to find you here by herself and she's only eight. She's a force of nature Jack, accept it. Besides can you think of anywhere else where she'll be able to make full use of her talents and not be exploited? I'm not suggesting she goes on field missions Jack. Just give her a lab and she'll be happy. Besides if you want her to find the cure for the virus, she'll need more facilities than any of the usual labs can offer her..."

Jack look resigned. "I guess so. So if... and I mean if I recruit her to Torchwood she will be able to find a cure for the 456 virus?"

"Yes. She engineers a mutated strain of the virus that will protect people against the effects of the virus, effectively rendering it harmless. That's another reason it has to be Siân that comes up with the cure. The governments of the Earth will never put their trust in something presented to them by an alien, not when every human being on the planet will need to be inoculated.

"But the 456 will still attempt to take the children," Jack commented.

"They'll try. But with the adult population still functioning, the weapons of the day will be sufficient to see off the 456 attack."

"I'm glad," Jack said earnestly. "I'm glad Ianto didn't die for nothing. I'm assuming that's where Siân gets the samples of virus from. That's really why you were checking Ianto's body isn't it? To make sure there was still live virus present in his system."

Clearly Jack really hadn't believed him when he had said Ianto was not dead, either that or he was fishing. Deliberately ignoring the bait the Doctor tried to sound nonchalant, determined to finish his explanation before Jack inevitably lost his focus, "I guess so. If the government followed their usual protocol I would think they burned the bodies from Thames House to destroy the evidence. By saving Ianto's body and placing it in cold storage you actually ensured the continued survival of the human race. Without it Siân would never be able to find the cure."

"Like I said, the government owed me a favour."

"They did you a bigger favour than you know Jack..." He stopped and looked uncomfortable, now that the moment was here he didn't quite know what to say. "You better sit down." It seemed appropriate in the circumstances.

Jack raised his eyebrows. "I am sat down," he said slowly.

The Doctor looked vaguely startled, "Oh, so you are. Sorry. Like I said before Ianto's not dead." The words tumbled out in a rush.

"And like I said before, I don't believe you. I felt his heart stop. I took his last breath into my own lungs. I felt him die. He's dead." Jack voice had turned cold again.

"The virus doesn't kill, Jack. That's one of the first things Siân found out. It induces some kind of suspended animation, indistinguishable from death to all intents and purposes." The Doctor's voice was low and earnest, all trace of levity extinguished. "Think about it. It makes sense. The 456 use children to provide chemical stimulants, but only young children. Once they are too old they would be useless to them. If they want a continued supply of their fix, the 456 would have to retain a breeding stock to create new children. It's a brilliant plan if you look at it objectively. Keep the adult population in suspended animation where they can't make any trouble then wake up a select few when they need fresh supplies. I'm guessing they must have tried cloning the original twelve children they took back in '64; that would have been the best way to ensure a continuous supply. But it can't have worked. Maybe clones didn't produce the same high that the original children did. That's why they came back in 2009. In the first instance they needed new blood; the children from 1964 were probably just about at the end of their useful lives. The second reason was to test the virus prior to launching an all out offensive. When they released the virus into Thames House it was the perfect trial; release the virus into a closed system, monitor the effects from inside their little glass house, and be confident that if it worked as it should, everyone would think the people affected were dead. Then they could take the information back home to apply on a large scale at a later date."

"But that doesn't change the fact that I died," Jack insisted.

"I don't think you did," the Doctor argued. "But I think the virus took you so close to death that it was enough to trigger your regenerative powers. By returning you to your factory settings, so to speak, the virus was wiped from your system."

"Alright, say I believe you and Ianto is just in a state of suspended animation what good is having the cure going to do. From what you said it only protects people from contracting the virus, not those people already affected." But there was a new glimmer of hope in his eyes.

"Ah but it does... well should. When Siân tests the vaccine on a sample of Ianto's blood she finds that not only is the virus eradicated, but that the cells slowly start to metabolise and eventually undergo mitosis. Essentially they come back to life. There is no reason why the same shouldn't happen if Ianto was to be injected with a dose of the vaccine. He should wake up."

The Doctor watched as a million different emotions waged war in Jack's eyes. Finally the piercing blue eyes settled on the one he'd been hoping to see. Sheer, unadulterated joy.

"Are you honestly telling me that I can get Ianto back? Get a second chance?" Jack's eyes blazed with fervour.

"Absolutely!" the Doctor said happily. He really liked the good days. "You'll have to wait a while though. Twelve years to be precise."

"Doctor, I was buried alive for two thousand years," Jack laughed. "Twelve years is a mere blip in time."

"I do need to warn you Jack. I don't know what effect being in suspended animation for that long will have on the human body. There may be side effects..."

A little later, sat side by side on the sofa sharing the long awaited cup of tea, Jack thought about the Doctor's machinations spanning nearly a decade.

"This has been quite a long project for you hasn't it Doctor?" he said slyly wondering if the Doctor would confirm his suspicions. "I mean normally you're in and out in a matter of hours..."

The Doctor looked sideways at him, "There's no fooling you is there Jack? OK I admit, I'm busted. Ten years for you, about two weeks for me since I left you on Chiswick High Street. You wouldn't believe the amount of hopping backwards and forwards I've had to do just to keep up with you. Especially that thing with Donna's coma. No way was I expecting that one."

"This was that important?" Jack pressed.

"Nothing more important," the Doctor affirmed. "The whole of human existence remember? I needed to make sure it played out the way it was supposed to before..." He fell silent and refused to meet Jack's eyes.

"Before what?" Jack insisted, a frisson of fear running down his spine.

When the Doctor finally spoke his voice was low and, Jack realised, tinged with fear.

"Something bad is coming. In the darkness. It's been foretold. He is coming in the darkness and he will knock four times. I think I'm going to die Jack, and soon. I needed to make sure you and Donna, and the Earth were safe before that happened. Who knows what my successor will do. I wasn't going to trust something this important to anyone else."

Jack didn't know what to say. He desperately wanted to contradict the Doctor's words, tell him that he was imagining things, but he found he couldn't. Something in the pit of his stomach told him that the Doctor had every reason to be afraid, especially if the man in the darkness was the man Jack suspected, impossible as that was. Briefly he wondered if the Doctor already suspected who the prophecy was referring to, or whether he should share his fears with him. One look into the Doctor's eyes told him the Doctor didn't need to be told anything.

With a wry smile the Doctor clambered to his feet,

"Time to go," he announced. "I think I'll pop back to 2059 and check that the Mars base is back where it belongs."

"Call in for a visit," suggested Jack with a smile.

"Absolutely, positively. Mars base first, Torchwood Cardiff second," the Doctor promised although Jack knew that he would never see the Doctor again, at least not in that incarnation.

"I'm never going to see you again," he said sadly. "Am I?"

"Oh I can absolutely promise that you will," the Doctor chuckled with one of his mysterious half smiles. "Might not be for a while though."

Jack got to his feet and held out his hand.

"Goodbye Doctor. And thank you."

The Doctor grinned. "It's a pleasure Jack. Any time." He took Jack's hand to shake it and found himself pulled into a mammoth bear hug.

"Look after yourself." Jack said seriously. "And if you need me you know where I am."

The Doctor nodded and headed out of the office back towards the TARDIS. He almost fell over the young girl crouching just outside the door. From her shivering it was clear she had been there some time.

"Did you catch all of that?" he said with a grin leaning down so only she could hear him. "You're going to change the world!"

Siân nodded, her eyes shining. "Are you him? The Doctor? The one grandad talks about?"

"That's me. The Doctor. Just the Doctor. Pleased to meet you Siân Harkness. Look after your dad won't you. He's a bit rubbish when he's on his own." He gave her a conspiratorial wink and she giggled. "And tell your grandad he did an excellent job. Right on cue. Just as we planned." Then with a swish of coat tails he was gone.

"Doctor!" Jack called after him, suddenly remembering he had one last question to ask, the question about his dream of Ianto, but his only reply was the whine of the TARDIS engines.

Final chapter coming very soon (cross my heart and all that) complete with lots of added Janto fluffiness...