Part 2: Destiny Undetermined

Four months after his official retirement date passed without his actually retiring, and almost a year after Sam's death, McKay showed up at Jack's office. Jack waved the scientist into a seat on the opposite side of his desk. He removed his reading glasses but continued to hold a pen in one hand – he had been in the middle of signing off acquisition requests when his XO had called through to let him know McKay had shown up and was asking for a meeting. Jack had no idea what McKay wanted; the last he'd heard McKay and Keller had gotten together – something which amazed him – and had left the programme, although unfortunately Keller had died a month before. A twinge of compassion had Jack putting the pen down; he knew only too well what it was like to lose the woman he loved.

Jack nodded across the desk. 'I'm sorry.' He saw McKay's surprise. 'About Jennifer.'

'Thank you.' McKay said sadly. He fidgeted nervously. 'I guess you're wondering why I'm here.'

'The thought had crossed my mind.' Jack said caustically.

'Actually, I was surprised to find you here.' McKay gestured wildly at the office. 'I thought, you know, you would have…uh…'

The physicist clearly struggled to find a diplomatic phrase and Jack wondered whether McKay had believed Jack would shoot himself after Carter's death or was just amazed that he hadn't followed through on his retirement plans. Jack was certain the latter had surprised a lot of people but after Sam's death he had felt he owed it to her to continue with the fight – especially when Woolsey had been appointed as Atlantis leader. 'What's this about, McKay?'

'Right. Straight to business.' McKay pointed at him and tried a smile. 'As always.'

Jack raised one eyebrow. It was enough of a threat.

'I know how to fix everything.' McKay said excitedly.

'Everything?' Both of Jack's eyebrows rose in cynical scepticism.

'Yes.' McKay was nothing if not confident. He perched on the very edge of his seat. 'I think I know how to stop Michael and prevent the spread of the virus here.'

Jack stilled. Without any serious opposition, Michael was well on his way to conquering the Pegasus galaxy and Jack had a gut feeling that Michael wouldn't stop at the one galaxy. More importantly, the virus that had plagued the Pegasus galaxy was beginning to spread across Earth – and that most definitely was a problem. 'OK. You got my attention.'

'Do you remember when you and the rest of SG1 went to the past?' McKay asked.

'Which time?' Jack asked.

'The first time; nineteen-sixty-nine.'

'Sure.' Jack said slowly. 'I remember.'

'Good, well, there's a temporal theory that suggests that an effect may precede the cause.' McKay gestured at him. 'In your case, SG1's trip back likely caused the Stargate programme to be reinstituted by the Air Force and Catherine Langford enabling the future to transpire so you would be able to travel back in time.'

'Your point?' Jack asked impatiently.

McKay's enthusiasm dimmed a little. 'Right. The point.' He cleared his throat. 'I believe we're experiencing a timeline that is not supposed to exist.'

There was a deathly silence.

'McKay…' Jack began.

'Look, hear me out here, OK?' McKay jumped up and started to pace. 'I know this sounds crazy but I think I'm right.' He took a quick breath and continued before Jack could interrupt. 'I think we're in a timeline that needs to happen in order for us to change the past.'

Jack sighed. It had been a long time since anyone had tried to confuse him with technobabble and given McKay wasn't Carter, his tolerance level was about out. 'What?'

'You know I worked out that John Sheppard was thrown forty-eight thousand years into the future.' McKay said turning to look at him hopefully.

'Oh. That.' Jack looked at him bemused. 'So?'

'So, if Sheppard is in the future, I believe we can help him get back to the past.'

'And that's going to help how?' Jack bit out.

'If Sheppard gets back to the past, we can make sure this timeline never happens.' McKay made a vague notion. 'Gone. Erased. Just like that.'

Jack lowered his hands to the desk and pushed himself to his feet. 'Maybe I didn't make myself clear before.' He paused for effect. 'What the hell are you talking about?'

'Ah, well I think I've narrowed down the pivotal event in this timeline that enabled Michael to get such an advantage.' McKay shook a finger at him. 'I believe if we can get Teyla away from Michael before the birth of her son, we can prevent Michael from using him to build his army and…you know,' he made a hurrying gesture, 'taking over the galaxy.'

Jack stared at him. 'And we do that…'

'By giving Sheppard the information he needs to save Teyla in the past.' McKay said as though it was incredibly obvious. 'Like that note you sent yourself once.'

There was another silence.

'So,' Jack straightened, 'you want us to help Sheppard in the future get back to the past to fix the present by wiping it out of existence.'

'Exactly.' McKay beamed at him like a proud teacher.

Jack was torn between being impressed at the audaciousness of the plan and exasperation. 'You ever heard of causality, McKay?'

'Well, that's why this plan is genius.' McKay said passionately. 'By us helping Sheppard get back to his own time, we would enable an effect in the past,' he pointed behind him, 'and by effect I mean stopping Michael.'

Jack looked at him blankly.

McKay waved his hands around his head. 'Look, the point is that we can stop this from happening.'

'Well, why didn't you just say so?' Jack said dryly, sitting back down.

'I thought I just did.' McKay said bemused.

'And you're not just doing this because of…Jennifer?' Jack asked bluntly, hiding his compassion when McKay flinched. 'Because changing the timeline will bring her back?'

'Does it matter if I am if everything else changes too?' McKay argued back.

Jack leaned back. He could understand McKay's grief, his loss. Did it really matter if McKay's motives were personal if he ended up saving two galaxies, he asked himself? 'And you have a plan for how we can do this?' He questioned pointedly.

McKay nodded eagerly. 'At first, I was thinking I'd have to come up some new physics so I could predict a way to get a message to the future and help Sheppard get back to the past but I then I realised there's another way.' He paused as though waiting for Jack to supply it.

Jack leaned back in his chair and glared at him.

McKay retook his seat. 'The time machine.'

'The time machine.' Jack repeated.

'Yes. The one SG1 found and used to go back to the past to get the ZPM.' McKay said, gesturing again. 'We fly it to Atlantis and jump into the future; get Sheppard; take him back to the past with the information and then…'

'And then?' Jack prompted.

'Well, I haven't quite worked that bit out.'

Jack sighed. It was almost a good plan. 'McKay…'

'But don't worry; I'm very good under pressure. Sheppard will tell you that and I'm sure I'll come up with something.' McKay pushed on.

'McKay!' Jack snapped.

McKay stopped and sat back. 'Sorry.'

'It's not a bad plan.' Jack allowed.

The physicist brightened.

'There's just one problem.' Jack said, leaning forward to rest his hands on the desktop. 'The time machine doesn't work.'

'The…what?' McKay stared at him. 'But it has to work.'

'Well, it doesn't.' Jack picked up his pen and fiddled with it. 'When we first ran into the Ori, we considered it as an option.'

'You were going to go back and stop us from ever coming across the Ori.' McKay realised. 'Look,' he said urgently, 'it doesn't matter, I can fix it.'

Jack bristled slightly. 'Carter couldn't fix it.'

'Ancient tech wasn't her area of expertise.' McKay shot back. He held Jack's gaze. 'Please.'

Another silence.

Jack slowly nodded. 'OK. I'll arrange for you to take a look at it.'

McKay let out an audible breath of relief and jumped to his feet. 'Thank you. You won't regret this.'

'Make sure I don't.' Jack said as he waved McKay out of his office. He waited until the door shut behind his guest before he made a call to Area 51 and arranged for McKay to work on the time machine, justifying it on the basis that they could always use another puddle-jumper. He frowned. He had worried if McKay's motives might be personal but he couldn't deny his own were similarly confused. If McKay was right, the timeline would change and Carter wouldn't die…a knock on the door caught his attention and he called for the person to enter as he resumed a position that suggested he had been working rather than thinking.

Daniel walked in. 'Hey.'

'Hey.' Jack frowned. 'Were we supposed to meet?' He'd been forgetting things of late.

'No.' Daniel gave a shy smile. 'I was in the neighbourhood for a budget meeting for the SGC. You want to grab some lunch?'

'Sure.' Jack got to his feet. 'I could eat.'

They ended up in a restaurant downtown. They covered recent personal events over starters and mains; Jack covered McKay's plan over dessert.

Daniel sipped his coffee and stared at Jack. 'You're kidding.'

'Nope.' Jack finished his cake with a flourish. 'He's serious.'

'And you're actually letting him take a look at the time machine?' Daniel's eyes were incredulous behind the panes of glass.

Jack shrugged lightly. 'Carter couldn't get it to work, Daniel. I doubt McKay will.'

'And if he does?' Daniel prompted, his fingers tightening around the thin ceramic mug he held. 'Have you thought about the consequences of changing the timeline? I mean, you're talking about changing the future of everyone in two galaxies. Do you…we even have the right to do that?'

'I don't know, Daniel.' Jack replied sarcastically. 'What I do know is that we're looking at this virus wiping out most humans in two galaxies and Michael ruling with his band of merry Wraith mutants. Carter died trying to prevent this from happening and I don't know about you but it's not the future I've been fighting for all these years.'

'I agree but,' Daniel sighed, 'changing the timeline is huge, Jack.'

'McKay figures it's all destined.' Jack took a sip of beer.

'That in deciding to help Sheppard get back to the past, we're actually creating the future that should have been.' Daniel surmised rapidly.

Jack pointed his beer bottle at his old friend. 'Something like that.'

'I guess he could be right.' Daniel admitted slowly. He kept his eyes pinned to Jack. 'You're going to help him, aren't you?'

Jack considered how to reply for a long moment before he cleared his throat. 'If he gets the time machine to work, I'll help him.' He let his eyes drop. 'Ever since…,' he stopped for a second, 'ever since Carter died, it's been like I've just been waiting for something like this to happen. Some crazy idea that will save us all.' His eyes moved back to his friend. 'And if it stops all this from happening, how can I not help him?'

Daniel nodded. He raised his mug. 'Count me in.'

But the mission was not to be. It took McKay a month to end up back in Jack's office.

'It can't be fixed.' McKay admitted unhappily. 'I've tried everything and every time I think I've got it, something else just doesn't work.' He paced back to Jack's desk. 'It's like someone figured out how to stop anyone from ever using it.'

Jack figured that someone was Carter, or a previous version of Carter; one who had lived out a life in the distant past.

'I'm sorry.' McKay finished abruptly. 'The plan won't work this way.'

'There's another way?' Jack asked surprised.

'Of course.' McKay looked at him as though he was dense. 'Through the wormhole like your trip to nineteen-sixty-nine.'

Jack looked at him bemused. 'Don't you need a solar flare for that?'

'Yes,' McKay pointed at him, 'which is the problem. I'm going to need to work out how to predict a solar flare on the Atlantis sun thousands of years from now, a flare that would be able to direct Sheppard back to the past at the right time for him to get back and save Teyla. And of course, some way of actually telling Sheppard all this.'

'Can you do it?' Jack asked seriously.

'Well, I've been working on some theories…' McKay trailed off at Jack's hard stare. 'No.'

Jack sighed heavily.

'You have to understand, this is a whole new ball game. I'm going to have to create a whole new set of math for this.' McKay explained.

'So, we're looking at…'

'Years.' McKay admitted. 'But it doesn't matter. Even if I spend the rest of my life doing this, if I get it right then the timeline will reverse back to the moment Sheppard gets back to Atlantis.'

'I'm probably not going to be around to help you when that happens.' Jack pointed out.

'Right.' McKay looked panicked for a moment before he shrugged. 'I guess I'll have to take my chances in the future.'

Jack winced at the statement. He stood up. 'Well, good luck.'

'Thank you.' McKay said. 'Again.' He nodded awkwardly and made to leave. He was at the door when he turned back. 'You know I didn't get it.'

'Get what?'

'When we first met,' McKay explained, 'I didn't get why you would stop all travel through the gate to save your friend no matter how long it took.' The scientist looked back at Jack sincerity shining from his eyes. 'I get it now.'

Jack nodded in understanding.

McKay left his office and Jack reached for the phone. He dialled the number from memory.

Daniel picked up at the other end. 'Hello.'

'It's me.' Jack announced. 'I just got a visit from McKay.'

'He couldn't get it to work?'

'No.' Jack twisted the cord between his fingers. 'There's a plan B.'

'Solar flare?' Daniel guessed. 'Message through the gate.'

'Yeah but he thinks it could take years.' Jack said. He shifted the receiver to his other hand and leaned back.

'I'm sorry, Jack.'

'You know the hell of it is that I think he could do it.' Jack sighed heavily. 'Only I won't be around to help him.'

Daniel was silent.

'Hello?' Jack checked. 'You still there?'

'Hmmm?' Daniel suddenly surfaced. 'Sorry, I was just thinking. Can't you send a message to someone in the future too telling them to help McKay?'

'Daniel…'

'I mean, like a standing order or something?'

Jack stopped to think about the idea. 'That could work.' He wrapped up the call and pulled out a sheet of paper. He scribbled his order onto it and tucked it into an envelope. He looked at the sealed order on his desk and something settled within him. There was a plan; it would work.

He took a long look around his office and his eyes settled on one of the pictures on his desk. He picked up the snapshot of him and Sam sitting on his fishing dock years before; just after they had defeated the Replicators and the Goa'uld – before the Ori and the realisation that Atlantis had discovered the Wraith. They had thought the fighting was over. For him, Jack realised, it finally was. A sense of peace descended on him; he was done waiting for something to happen; done fighting.

Maybe it was time to reconsider the retirement.

To be continued in Part 3