Rourke turned to take in the bridge. ‘What’s this – a Luna-class?’

‘Insignia.’ Valance’s voice was low, flat, and was staring at the command chair. ‘This is the USS Derby.’

‘Oh.’ He looked at the officers in the last generation’s uniform, many of them very junior, and when he followed his gaze he saw her. A youthful Lieutenant Valance in the central seat. ‘I reckon this isn’t just the Gamma Shift.’

‘No,’ said Valance, looking between herself and the viewscreen. ‘It isn’t.’

‘Lieutenant,’ said her younger self, hitting a comms button on her armrest. ‘I want you to prepare a rescue party. This is going to take a boarding mission.’

‘Boarding?’ That was a blue-shirted officer in a Lieutenant Commander’s pips. ‘Lieutenant, we’re heading to negotiations.’

Lieutenant Valance shook her head. ‘That’ll keep them occupied. They’ve got our senior staff; they won’t just hand them over. Not without huge cost to us, or huge cost to the stability on Plutark.’

Rourke looked between them, then at Commander Valance. ‘Staff officer scientist getting uppity?’

Her expression was cold. ‘Chief Medical Officer. Doctor Minnow advised caution and diplomacy.’

‘While you’re normally so gung-ho.’

She didn’t speak for a moment, listening to her younger self launch into an explanation. ‘This was a long time ago.’

Realising he’d get more answers from observing he did so, and couldn’t help but raise an eyebrow at how different Lieutenant Valance was: animated, impassioned. ‘Risky,’ he said as the young officer laid out her plan. ‘Double-crossing a hostage negotiation?’ He felt his chest tighten at the thought, and didn’t say more.

‘That’s what Doctor Minnow said,’ said Commander Valance, right before Doctor Minnow told her past self exactly that. ‘But I thought I knew better.’

He turned to the viewscreen, showing the gentle turn of what he assumed was the world of Plutark. Then he looked at the uniforms, the displays, and finally Lieutenant Valance yourself. ‘You’re very young. What’s this; ten years ago? How high were you in the chain of command?’

‘Third officer,’ she sighed. ‘The captain was injured, she’s incapacitated in sickbay. The XO and Second Officer were abducted by the extremist faction I’m about to double-cross in negotiation, along with some other officers. And formally Doctor Minnow isn’t in the chain of command. Formally, Doctor Minnow hasn’t passed a bridge officer’s exam.’

Rourke took in the lines of experience stamped on Doctor Minnow’s face, the steel in her hair. ‘But Doctor Minnow has seen about four times as many crises as you.’ He looked back at Commander Valance. ‘Your plan is risky. I say that as an expert in this area. You ignored Minnow and the senior staff paid the price?’

He watched a muscle twitch in the corner of Valance’s jaw. ‘Let’s see.’ She looked back at her younger self, arguing still with the doctor.

‘There is a risk-reward factor,’ Doctor Minnow was saying, her voice low and level. ‘The longer we keep the commanders alive, the better. If we can enter into negotiations, they have to know that we cannot simply resolve their objections with the government of Plutark. They can’t expect to give us our people back, and in response we support them wholesale.’

‘You’re not making negotiation sound promising, Doctor,’ said Lieutenant Valance, not even watching Minnow as she studied a PADD.

‘We have to assume they’re rational actors,’ Minnow pressed. ‘Some of their grievances even have merit. We can support Federation interests and get our people back if we offer to act as go-betweens for them and the government. Bring their grievances to the table, get the government of Plutark to look at them.’

‘Giving them what they want because they abducted our people isn’t a good look for Starfleet.’

‘Then don’t frame it like that,’ said Minnow. ‘Say that you’ve seen they have a reasonable cause but you can’t possibly assist them in peaceful resolution with the government so long as they have our officers. But if they free them, this demonstrates them as rational and reasonable, and means Starfleet can assist as neutral arbitrators.’

Rourke clicked his tongue. ‘She either has a solid point or is very naively hoping that you’ll be negotiating with people who have the authority, as well as reasonable mentality, to reach that decision.’

‘It was impossible to say,’ said Commander Valance. ‘But this was the point I told her to go see to the captain.’ They watched Lieutenant Valance, and Rourke found his chest still oddly tight. Not for his own ghosts, but he could see the burdens on the young officer’s face. Unlike his XO, she was expressive, emotive. Unlike his XO, this young woman showed her struggles.

And at last Lieutenant Valance drew a deep breath. ‘Alright, Doctor,’ she said. ‘Let’s try it your way. But I’m going to keep the security team on standby.’

Commander Valance gave merely a huff in response. ‘I dare say we won’t see how that pans out.’

‘Except if this is anything like what happened to me, it ends up with you as a full Commander and the CO of the Odysseus by 2399,’ said Rourke bitterly.

‘And possibly still an air-headed, hot-blooded fool who never learnt her lesson.’

He straightened at that. ‘What did happen?’

‘I got what I deserved, and other people got what they didn’t,’ said Valance, toneless again. ‘We rescued the officers, but it started a firefight in high orbit and I downed their ship. It crashed into the atmosphere and I had to order the Derby to pursue. We couldn’t stop them, but they were on a trajectory to crash into a major settlement. We had to use the tractor beam to deflect. The crew still died, along with three civilians.’

‘That sounds…’ Rourke frowned. ‘Not like something you could have anticipated.’

‘I anticipated I’d be opening us up to violence,’ she pointed out. ‘But I thought, like I always did back then, that I could pull us out of the fire on grit and wits.’

‘A lot of young officers feel like this. You were, what. 28?’

‘27. It’s no excuse.’

So you went on to stick to regulations and the book, Rourke thought as he watched her. So you shut down, because you didn’t trust yourself or your instincts.

‘You can’t assume -’ he began to say. And then, again, the lights died.

* *

‘If we recalibrate the sensors,’ Airex theorised aloud, ‘to scan across a quantum level, then we might be able to see what’s trapping us. Get a better examination of the anomaly. It might take recalibrating the internal sensors.’ A silence met him from the bridge crew, and he raised his eyebrows. ‘You disagree?’

Cortez and Lindgren exchanged glances, then Lindgren shook her head. ‘No, sir, you just… you made it sound like a suggestion. You don’t need our say-so to act on your theories.’

Oh, right. I’m in command. He drew a slow breath. ‘Of course. I don’t suppose we’ve been lucky enough to locate Thawn?’

Cortez shook her head. ‘It looks like anyone who was below deck 15 when we hit the anomaly is… unaccounted for. Records suggest that’s Thawn and Kharth, as well as Rourke and Valance.’

He wondered if he’d caught something in her voice at the mention of Valance, then had to wonder if it was the way his own throat pinched at the mention of Kharth being missing. And decided that being in charge meant he didn’t have to think about his feelings. ‘We’ll make do,’ he said instead. ‘Lieutenant Drake, give me a hand with the sensor recalibration, then.’

Drake got up, not looking too optimistic. ‘Uh. I know how to handle navigational sensors…’

Airex tried to not look annoyed. His gaze went to Cortez. ‘Lieutenant?’

‘Like, I’m pretty genius,’ she said eloquently. ‘But quantum mechanics is not my forte. Besides.’ She stabbed a finger at her panel. ‘We are still losing what little power we have; we need to stop that, and that is my area of expertise.’

He blew out his cheeks. ‘Who’s not stuck in the anomaly?’ He went to the command chair only reluctantly, and brought up the holo-display for personnel down in Ops’ computing division. ‘No Athaka, no Bekk. Blast it.’ But he did spot a name, and hit the comms panel. ‘Bridge to Doctor Logan.’

A long pause. ‘Uhhh.’ Another long pause. ‘Are you sure you really want me?’

He’d met Josephine Logan when she’d boarded, and otherwise left the academic to her own research and her own management of Ops training. Once he might have relished engaging with the researcher, but instead he’d found himself always with something better to do with his time. ‘Doctor, this is Commander Airex. The ship is definitely in a crisis, yes, but I need assistance in maximising our computational processing speed to conduct and analyse sensor scans on a quantum level. I can’t get Lieutenant Thawn and there’s a programming element which is… a challenge for me.’

‘I don’t… I mean, I’d really need to know more but that’s theoretically -’ Another pause. ‘Are you asking me to come to the bridge?’

He rubbed his temples. ‘Are you unharmed, Doctor?’

‘Oh, I’m fine. I’m under my desk,’ said Logan. Drake gave a one-shouldered shrug, like this was a reasonable action. ‘Can I get to the bridge?’

‘You’re only a couple of decks down. Do you have a PADD near you?’ Airex picked up his own. ‘I can transmit you the route through the Jefferies Tubes. If you can get a light.’

‘It’s – it’s pitch dark down here.’

Airex tried to not frown. ‘If I send -’

‘No. No, you’ve got a crisis and I can help. Uh. Is Commander Rourke up there?’

‘We’ve lost contact with the deck Commander Rourke’s on. I’m in command.’

‘Oh.’ He wasn’t sure if she sounded worried or relieved. ‘Send it. I’m on my way. Logan out.’

Drake looked over. ‘So we get the civvie programmer to recalibrate our sensors.’

‘We don’t have enough information on what this anomaly is because we can’t detect it properly.’ Airex frowned at the display of what limited data they had. ‘I’m theorising we’re stuck in a breach to a quantum or parallel reality.’

‘What’s the difference?’ said Lindgren.

‘Scientifically, they’re the same,’ said Airex. ‘The theory of quantum universes suggests there exist alternate timelines in which any possible outcome of any single event in the history of space-time has come to pass. And matter in each of these resonates on the same quantum level as all other matter of that universe.’ He put down his PADD, moved back to the science console where he felt much, much more comfortable.

‘I’m concerned about the distinction,’ he pressed on, ‘because colloquially, we refer to a parallel universe as one akin to our own. The same laws of physics, biology – science – apply in a way with which we’re familiar. It’s been suggested that these have a much more similar, if distinct, quantum signature and it’s easier, when confronted with a quantum breach, for us to interact with those. Some of these parallel universes have been identified which are personally recognisable. In which the course of one’s own life has taken different turns.’

‘How does that help us?’ said Drake.

* *

‘It doesn’t yet,’ Lieutenant Davir Hargan told Captain MacCallister. ‘But it’s preferable to the alternative, in which we’re slipping into a vastly different quantum reality, wherein no recognisable laws of science apply, or anyone or anything we encounter in it is vastly unrecognisable.’

‘Yeah, at least I can confirm we’re from a fairly close reality,’ said Kharth, arms folded across her chest. ‘I’ve not noticed gravity working upside-down or anything.’

Davir’s expression pinched. ‘Gravity wouldn’t work upside-down – there’s no cosmic down.’

‘I was being colloquial, Dav,’ she said before she could stop herself.

His gaze brightened. ‘This really is fascinating.’

‘Sure,’ said Commander Robert Templeton, leaning against the XO’s chair. ‘Except that our Kharth and Thawn are either stuck somewhere on the ship we can’t reach, or are stuck in another reality.’

‘Along with most of your ship itself,’ Kharth agreed. ‘And my ship.’

Thawn piped up, voice low. ‘Can I ask what Endeavour was doing before this happened? Where are you?’ She hadn’t spoken for much of the last ten minutes, and Kharth had watched her studiously Not Looking at Noah Pierce.

‘This was just a survey mission,’ said Templeton with a sigh. ‘The Romulan Republic invited us to conduct scans along the old Triangle and into the Azure Nebula. It’s still a bit of a wild place, so Endeavour was sent.’

‘So you’re not,’ said Kharth, ‘hunting down the outpost of a dangerous, murderous pirate gang called the Wild Hunt?’ The other Endeavour’s crew exchanged looks. She hummed. ‘I guess things are pretty different.’

Davir Hargan still leaned across his console. ‘But you know all of us.’

‘Actually,’ said Kharth, ‘I don’t know him.’ She nodded at Templeton. ‘And I never met Captain MacCallister or Lieutenant Pierce.’

‘Why not?’

‘Well.’ Kharth shrugged. ‘There was a Wild Hunt attack on Endeavour, before I was assigned. Captain MacCallister was hospitalised long-term, like Thawn said. Lieutenant Pierce is dead.’

Noah Pierce was over at Comms with Ensign Lindgren, and looked up, doe-eyed. His gaze quickly went from her to Thawn and back again. ‘Dead?’

She saw Thawn hesitate, and decided to not drop her in it. ‘Bridge explosion in the pirate attack. Apparently.’

‘So – this is fascinating.’ David Hargan didn’t seem at all put off by this revelation. ‘In your reality, you and I only just transferred to Endeavour?’

She turned back to him and drew a slow, tense breath. ‘No. You’re joined to the Airex symbiont and have been on Endeavour, what, three years? I was on Starbase 371 all that time. I hadn’t seen you since we were on the Cavalier together.’ One thing she’d desperately not wanted to ask was if Davir Hargan and the Saeihr Kharth of his universe were still in a relationship. The look on his face as he put it all together gave her the answer, and in his silence she turned brusquely to MacCallister. ‘This might be fascinating, but we still have two ships in two universes stuck in the same anomaly.’

* *

‘I’m reading,’ said Josephine Logan as she leaned over the Ops console, ‘no less than seventeen hundred USS Endeavours trapped in this quantum anomaly. All existing in the same space-time simultaneously, but of course, it’s different. And that’s across ten times as many quantum realities this anomaly is bridging.’

It had taken the doctor ten minutes to climb to the bridge. Another five to bring her up to speed, but she’d grasped the concepts Airex was wrestling with quicker than Drake or even Cortez. Reconfiguring the sensor array and, more importantly, maximising the computer’s processing speed, even as it lost power, to be able to analyse the data of vast readings on a quantum level had taken at least thirty minutes. Alone, Airex knew it would have taken him three times as long.

Drake let out a low whistle. ‘Holy shit.’

‘This is amazing,’ said Airex, ‘but can be studied at-length in the logs once this is all over and our ship is safe. Lieutenant Cortez, what’s our systems status?’

‘We’re still losing power,’ said the engineer. ‘But the doc’s findings have given me an idea.’ She hit some controls, checked some readings, and sucked her teeth. ‘Yep. That makes sense, and it fucks us.’

Logan looked up, eyes wide. ‘What?’

‘There’s some overlay of the different Endeavours. Obviously physical matter isn’t existing all in the same space-time or we’d be smooshed into one,’ said Cortez. ‘But we don’t have enough power for all of the ship’s systems. I think to some extent energy is co-existing across all quantum realities simultaneously, which means the Endeavours and anything else out there are feeding off the same collective pool of power.’

Drake rubbed his temples. ‘God, I wish I was the one stuck in a turbolift.’

‘So…’ Logan winced. ‘It’s causing massive power fluctuations. Because the average power level of the Endeavours isn’t going to be 100 percent, that’s statistically impossible. It just takes several of those Endeavours to have lost power due to the anomaly or some other form of damage, and now the energy to power less than seventeen hundred Endeavours is trying to power seventeen hundred Endeavours.’

‘And it gets worse,’ said Cortez. ‘Power fluctuations are increasing, and power flow is harder to regulate, on the decks and systems closer to Deck 15 – closer to the anomaly. So proximity is… making us share space more? Or at least energy?’

Airex’s eyes widened as he rounded back on Cortez. ‘The warp core?’

‘Yeah, that’s the worse news. If the scans are right, we – and most of those other Endeavours – are sinking further into the anomaly. Which means at some point, maybe simultaneously, all of our warp cores are going to fall into the anomaly, and if the doc’s right, then all of our warp cores are going to exist in the exact same point in space-time and on a quantum level simultaneously.’

Drake looked between them. ‘Alright. It’s my job to say, “So?” isn’t it?’

Airex actually shrugged. ‘I don’t know what that means.’

‘Matter and anti-matter is an incredibly delicate mix,’ said Cortez. ‘How much do you want to bet that seventeen hundred M/AM Reaction Chambers coexisting at once ain’t gonna be delicate?’

‘I think I can translate that,’ said Lindgren sadly. ‘Boom?’

Cortez nodded. ‘Big boom.’