After Crossing.

Julian Bashir first thought he was still on Terok Nor station under the command and control of the so-called Klingon-Cardassian Alliance, but as he and Major Kira walked to the infirmary for a check-up, Julian was eternally thankful for his - secret - genetic enhancements; without them, he might have collapsed by now due to the exhaustion he was still feeling after working in the ore processing centre.

But this was not the same station; there were no armed Klingon or Cardassian guards. No tired and exhausted Terran slave workers. No Bajoran soldiers with those weird cross-belts. No, Deep Space Nine's familiar Cardassian architecture was still dark, oppressive, alien, but it was warmer here and there was more light which made the place more welcoming than its cold counterpart.

As he and the major were escorted to the infirmary, Julian noticed everyone was looking at them in shock; some people who were moving through the promenade were slowing down to a halt as they caught sight of his dirty hands and face, and his torn uniform, but he got the impression everyone was paying more attention to Kira rather than himself.

It was likely nobody had ever seen Kira Nerys wearing anything that sheer in their entire lives. But he was too tired to really care. All he wanted was to get the checkup done and then get to bed. He could write his report on his experiences in the parallel universe in the morning, all he wanted was to get a bite to eat, and then sleep.

Sisko and Odo were waiting for them in the infirmary. Julian knew it was almost childish, but he shied away from Odo, just slightly. All he could see was the changeling's brutal and bullying counterpart who had quoted one rule of obedience after another while he victimised and bullied the other slaves in the processing centre.

Sisko folded his arms and looked them over, his eyes wide as he took in his station doctor's state and his first officer's skimpy attire. "What happened out there?" He began as soon as the nurses stepped in to examine the duo.

Julian closed his eyes and sent a look towards Kira, hoping she would see and realise he wanted her to begin. Fortunately, she noticed, although she did send him a concerned glance. "We fell into a parallel universe just as we entered the wormhole, Commander."

"What?" Sisko whispered in surprise.

"We fell into a parallel universe," Julian nodded in confirmation. "There was some kind of fault with the impulse engines, and as we travelled through the wormhole there was a flash of light. We both experienced a brief sense of dizziness, but otherwise, we were fine. But when we reached the mouth of the wormhole, we found the station was orbiting Bajor."

"We were intercepted by a Klingon cruiser; two Klingons boarded the runabout," Nerys took up the story, "as soon as they saw me they were frightened of me."

"Frightened, why?"

"Because of my counterpart, the Intendent of Bajor. When we arrived at the station, we saw humans as slaves, and that's not all; we learnt there was an alliance between the Klingons and the Cardassians. They had overthrown an empire created by Terrans. A century ago, a starship captain named James Kirk crossed over into another universe," Nerys explained.

Sisko took a deep breath. "The transporter accident? I remember reading about it at the Academy."

"Was it important?"

"James T. Kirk is one of the most famous officers in Starfleet history, Constable," Bashir explained for Odo and Kira's benefit, "at the Academy, all Starfleet captains who've reached that kind of status are required study. His account of accidentally transporting into a parallel universe is well known, but we didn't expect to be told the earlier visit had massive consequences for the Terran Empire, the organisation which is the counterpart to the Federation of that universe."

"Let me guess, Kirk's suggestion to Spock, his first officer's counterpart in the Empire opened the way for the Terran Empire to be torn down?" Sisko asked his rhetorical question.

"My counterpart hinted it happened around the time Bajor was held under Terran occupation; by the time the Klingons and the Cardassians allied themselves with one another, the Terrans were unable to do anything about it," Kira shook her head in pity and annoyance her world and her people seemed to enslaved no matter what universe they were in. "I just don't understand what it is about Bajor which makes her a prime target for occupation."

"There might be a reality it never happened, Major," Sisko said soothingly before he shook his head as he considered the ramifications of what he had just heard, and what kind of effect this would have back at Starfleet Command. Some of the admirals would likely claim this was one of the best examples of why the Prime Directive should be held up, but with Kirk long since dead the chances of getting a conviction were moot.

Not that it would have stuck since Sisko knew Starfleet had long since considered the matter moot anyway.

"Can the alliance come through the wormhole as you did?" Odo asked to fill the silence while Sisko looked at him in intrigue for even asking such a question. But he guessed it made sense; Odo took station security very seriously and since this was an accident, it could be duplicated.

"I don't think so," Kira replied but she didn't sound too certain, and she glanced at Bashir for his own opinion.

"I don't know myself, but if they didn't know about the wormhole before now, its likely they do now; we were chased to the wormhole by a Klingon ship. They were really close when we went in, but I don't think they followed us in."

"That sounds like they have only just discovered it," Sisko replied, already working out in his head what the Alliance would do with passage to the Gamma Quadrant, but he quickly found himself stumped; he didn't know enough about this parallel universe besides what he had learnt in the past and what he was hearing now. "If that's the case then they're busily studying what they've detected."

"I don't think it would take them long; I let slip we had passed through a wormhole, but they hadn't realised there was one," Kira confessed.

Sisko sighed.

He didn't know what the effects of a hostile power knowing about the wormhole would be, and what effect it would have on the balance of power in a parallel universe. There was nothing he could do, but he did have concerns.

"What happened?"

Bashir glanced wryly at Kira and then back at his superior officer. "I was put to work in the ore processing centre; the Terrans have certainly had the tables turned on them. They're a slave race now, although there seem to be different levels of slavery."

"What do you mean, doctor?" Odo asked, his beady little eyes narrowing curiously when he noticed Bashir shudder slightly at the sound of his voice. And it made the shapeshifter concerned. Why would the doctor who was usually so gregarious shudder at the sound of his voice? It only took him a moment to guess Bashir had met his own counterpart, and the encounter had not been pleasant.

Kira, also noticing the doctor's reaction, spoke up, "When we were on Terok Nor, we found the Terran slaves were divided into tasks; some of them worked in mines, others worked in ore processing centres, but there were others who worked as entertainment staff; my counterpart has someā€¦. Extreme tastes," she said delicately while she hoped and prayed to the prophets nobody asked her what she meant, but fortunately, both Sisko and Odo had enough sense not to ask for more details.

"But we learnt some Terrans are used as mercenaries, pirates; I don't know why, but when we got there we found your counterpart was one of those few who were used by the Alliance under a strange pretext for freedom, Commander," Kira said, looking up at Sisko.

Sisko was surprised to hear what his counterpart was doing in this other universe, and he wondered why and how his counterparts life had unfolded like that. But as he considered that, other questions entered his mind. Was his other self married? Did he have children? What had made him work for the Alliance, was it because he knew no other life and didn't see any way of overthrowing them? Sisko guessed that would make sense, but he mentally shook the thoughts off. His counterpart's life was nothing to him although it was interesting, and he focused on Bashir.

"I can guess how you got into that state, doctor. Ore processing."

Bashir nodded. "I got a bit mouthy with Garak's counterpart although it wasn't my intention to be rude. I was dragged to ore processing where I met Odo counterpart and O'Brien's. Odo ran the centre with an iron fist, bullying all the workers who were practically worked to death, I would not be surprised in the least if dozens of slaves tried to escape on a near-daily basis. To put it short, the whole system is a mess; O'Brien hinted there was some power fault, but nobody listened to him, and it blew up literally in their faces."

Sisko nodded and he looked between the duo. They were both tired, he could see that, and he could also see they wanted nothing more than to stop speaking. While he wanted to know more about what had happened, he didn't see the point in making them more tired after their rough little adventure, and besides, they were both shaken by what they had endured. He could find out more about what had happened to them later. "I want you both to leave after your check-ups," he said, looking to the nurses, but it seemed they were nearly finished, "but tomorrow I expect a full report by the end of the day. I'm not going to rush you; take your time to remember everything so I can despatch them."

Bashir and Kira both gave him looks of relieved gratitude. "Thank you, sir," Bashir replied.

Sisko nodded, and he left the infirmary. As he made his way back to his office, he thought more about the story that had been given to him by his officers. The idea the parallel universe, the so-called 'mirror universe' James Kirk himself had visited had changed so much with the Terran Empire being torn down, and replaced by an equally oppressive regime was a surprise. During his time at the Academy, when he had studied things like this parallel universe, Sisko had wondered what had happened there, whether the alternate Spock had actually considered Kirk's suggestions about recreating the Terran Empire, transform it into something less aggressive and piratical, and if he had even succeeded in that cutthroat world.

Judging from the sounds of things, he had succeeded.

Perhaps a little too well.

Author's note - I've become interested in alternate histories and alternate timelines. After rewatching the DS9 episode 'Crossover' I became inspired enough to write this one-shot. I hope you have enjoyed it.