AN: This story has been updated and re-edited slightly as of Tuesday 2nd July to remove several minor errors/inconsistencies. This is not an exhaustive removal, merely a spring clean.

Essentially, this story a great big mesh up of Star Trek and Mass Effect, with the times all messed up too (so please, with the greatest of respect, don't bother reviewing saying "Mass Effect happened in the 22nd Century", because I know; Mass Effect also didn't have Borg). A full timelines of altered events from the Star Trek side will be at the end of the story (as of writing this, as yet unposted).

Before we start, I'll warn you about a few things that might put you off reading - The Borg are the main villains (so if Voyager Borged you out, you might want to think twice before reading), a lot of the events are similar to Mass Effect but with a Trek twist (so if novelisations aren't your thing, even crossovered variations, don't read) this is going to be a Shepard/Tali fic (Talimancers forever!), and there are some non-canon Trek elements included (specifically Hazard Suits from Star Trek Elite Force).

I hope you enjoy reading this fic as much as I have enjoyed writing it.

Prologue 1: Galactic History In Brief.

Extract from "The United Federation of Planets: an in-depth study of the human race and its close allies, including their technological achievements" by Dr Vars Melron.

Foreword: A Brief History of the Federation.

It is perhaps one of the more curious things that can be noted about the nature of the universe that creatures with shorter life spans achieve a great deal more in their brief time than those with longer lifespans in the same given time. It is almost as if they are attempting to compensate for their lack of lifespan by achieving twice as much. This had been proven many times: after all, many greatly respected scientific minds in Citadel Space are Salarian, and so it is that humans - almost as short lived as my own illustrious species - have achieved so much after only a few short centuries of being a space-faring power.

The story of how humanity - and the United Federation of Planets they have formed, together with several other space-faring races in their local cluster - became an important power in Citadel Space began in a remarkably humble place, and yet this story demonstrates how humans can be a stunningly resourceful species. Shortly after a devastating conflict on their homework they refer to as the "Third World War", a nuclear conflict that nearly destroyed their species, a scientist named Zephram Cochrane, with comparatively few resources at his disposal and little help, achieved the first FTL flight (commonly referred to as the "first warp flight") in that species' history, in the experimental ship Phoenix. The Phoenix, built into the hull of a converted nuclear missile, was a primitive vessel, barely able to achieve the speed of light, and yet it's flight was enough to gain the attention of the Vulcans - humanity's first allies in space, and another space-faring power, albeit one relatively unconcerned with exploration.

Over the next few decades, with the help of their new allies, the humans began a process of scientifically-minded exploration of surrounding space as well as the expansion of the United Earth Starfleet, thanks largely to the efforts of Dr Henry Archer and his son Captain Jonathan Archer, the former a leading warp drive specialist who helped build the first Warp 5 engine (old scale - see Chapter Sixty, "Federation Warp Drive and it's Development", for details), and the latter the Captain of the Earth Starfleet ship Enterprise, the precursor to the Federation Starfleet's long line of vessels to bear that name (see Chapter Eighteen, "The Enterprise Legacy", for more details on this).

It is a tendency of some Citadel races to forget the importance of the Warp propulsion systems built by the humans, Andorians, Vulcans and other species from their corner of the galaxy when compared to the Mass Relays, but the achievements of these species must not be discounted. The Warp Drive may not allow for the speedy travel across the length and breadth of the galaxy in the same way the Mass Relays do, but importantly, they are the most efficient non-Relay travel methods known, and unlike any other Citadel species, these few did not utilise Prothean technology at all: every innovation, every single effort, every scrap of new technology – all of it came from the innovation of these species, not from the relics of a dead race.

Once humanity left their home system, they began (as I stated earlier) a process of exploration, sending their first Warp 5 ship (the Enterprise NX-01) on a mission that consisted of learning what was in the universe around them for its own sake, which, although it may seem a strange goal, was one that drove the human race's earliest attempts at space travel and in many ways still drives the Federation today. Despite obstacles, setbacks, early conflicts with neighbouring species and other incidents, the humans - thanks largely to efforts by the aforementioned Captain Archer - formed what is known as the "United Federation of Planets", an alliance of worlds not unlike the Citadel Council, but bonded more tightly: the worlds in the Federation no longer had their own defence fleets as the races of the Citadel do, but rather each contributed toward the new Federation Starfleet - a single military/scientific force that combines the roles of exploration and research with the role of a military defence force (for more on Starfleet, see Chapter Ten, "Starfleet: Force For Good?").

It was Starfleet that first discovered the Mass Relays and through them, the Citadel and surrounding space. The USS Enterprise NCC 1701-C, under the command of Captain Rachel Garrett, was sent through the relay to explore, utilising an experimental Mass Relay drive as well as its traditional Warp Core. Reportedly, the Captain was expecting more Prothean ruins, and was suitably taken aback by the presence of an alliance of powerful spacefaring civilisations, but nonetheless she opened diplomatic relations with the Citadel, establishing the beginnings of the relationship now shared between the Federation and the Citadel (see Chapter Three, "The Citadel and the Federation", for more details). Garrett's diplomatic prowess was such that her achievements, and those of her crew, were honoured by a statue of the Enterprise-C on the Presidium.

Since that time, now almost twenty years past, the Federation and the Citadel have maintained cordial relations, the Federation colonising many worlds in various regions of space it was previously unable to reach, and in return allowing Council races to have holdings in Federation space as they so choose, as well as the right to serve in the Federation's Starfleet, an honour that as of yet only a few members of the Citadel races have chosen to accept. For their part, the Federation have also helped mediate several important conflicts in Citadel space, but more importantly, they have defended not only their own colonies but others as well, earning the gratitude and respect of all the Citadel races.

Prologue 2: Starfleet's Finest.

2373.

Admiral Joseph Wilson of Starfleet Academy's application board looked over the latest applicant with some interest.

The Citadel races - the name given to most of the species beyond the Mass Relays - usually made up only a small percentage of total intakes at the academy. It was especially unusual to see members of the quarian people - nomadic travellers bereft of their own home-world - join up, and yet, here she was. A quarian female, young and looking very nervous, if her body language was any indication. Quarians were considerably more emotionally expressive with their body language than most other species tended to be; a cultural and sociological side effect of the environmental suits they wore.

Wilson was conducting her final interview - her aptitude rating for Starfleet academy was well within the acceptable bounds, and Wilson had no doubt she'd make an excellent Engineer on a Starship one day if admitted into the academy, but that was only going to happen if he said so, and he would only say so if he felt she was suitably Starfleet material. It was her aptitude that necessarily worried him, but her motivation.

"Well," he said, once she had entered his office and stood at rough attention, "you have technical skill and experience on your side, Miss... nar Rayya?" He hesitated, remembering long forgotten briefings on quarian culture. "No, forgive me, that's the name of the ship you were born on. It would be Miss Zorah, wouldn't it?"

"Yes sir," she said quietly. Wilson doubted she would ever have brought it up herself.

"As I said, you have the necessary series to join the fleet," Wilson continued. "More than enough in fact." The quarian shifted slightly under the praise, clearly not comfortable with it any more than she was the entire situation. "I have no doubt you'd be a boon to any ship you served on."

"Thank you sir," Tali'Zorah nar Rayya replied, formally. Clearly she was used to addressing admiralty, probably due to the fact that her life had been ship-bound.

"I do have a query about your intentions in Starfleet, however," the Admiral began tentatively. The young woman tensed slightly, possibly sensing that this was where her case to join the academy would be affected. "Specifically your intention to stay, or not, as the case might be."

"I'm afraid I don't follow, sir," Zorah said, sounding slightly confused.

"Then let me be plain, Miss Zorah," Admiral Wilson said, leaning back in his chair slightly. "We've had a few quarians join Starfleet before. So far none have stayed with the fleet more than a few months after gaining a shipboard posting. Most cite a 'pilgrimage' of some form as their reason for leaving." Wilson leaned forward. "I'm not going to bar you from entering Starfleet if you tell me now your intention is to do the same, that's not fair on you. But I need to make a note in your file if it is your intention to leave the fleet in the same way. It's unfair for a Starship Captain to get a skilled officer without knowing that officer is going to leave within a few months. That sort of thing can mess with the dynamic of a Starship's crew after all."

Zorah was silent for a moment, apparently considering his words carefully.

"Sir," she said at last, "I would be lying if I said my loyalty wasn't first to the flotilla." Wilson nodded, sitting back in his chair as he waited for her to continue. "But," she added, and a serious earnestness came into her voice, "I came here to join Starfleet. To learn about other cultures. To see new worlds. To serve on one of your ships - and believe me sir, those ships are truly beautiful, there's no way I'm going to give up the opportunity to work on one -!"

Wilson held up a hand to forestall her babbling, a smile on his face.

"So you're in the Fleet for the long haul?" he asked.

"As long as I'm wanted, sir," Zorah replied earnestly. Wilson favoured her with a smile.

"Alright then," he said, standing up and extending a hand. "Welcome to Starfleet, Cadet Tali'Zorah near Rayya."

"Thank you sir," the quarian replied, taking the hand and shaking it firmly. "I promise I won't let you down."

Saren Arterius, Turian and Spectre agent of the Citadel, blinked in surprise at what he just read. He must have misread the orders, he reasoned, because they could not be saying what he thought they were saying, that would just be plain stupid.

He read them again.

No. They still read the same when he re-read them.

No, this was silly. They couldn't be asking him to do this, there was no way they were being that stupid. Maybe… maybe if he closed his eyes and opened them again, the orders would not be what he was seeing in front of him...

No. Still pretty damn clear.

Damn.

'FAO: Saren Arterius, Spectre.

Having received and studied updated intelligence from the United Federation of Planets concerning a race called "the Borg", a scientific team has recommended locating, infiltrating and studying a Borg vessel and its occupants in order to better understand and combat the threat this race poses to all species in Citadel space. An opportunity to do so has arisen - a damaged Borg vessel has been located in the Artemis Tau cluster. Your mission is to secure it for study by whatever means you can.

Good luck.

Sparatus, turian Councillor.'

This was insane. Beyond insane. What this said… how could the Council think this was a good idea? Or even a passable idea? What idiot on the Council had ever approved this?

Saren had read up on the Borg repeatedly, of course, as part of his mandate to protect Citadel Space. Their abilities, their vessels - and the assimilation process. That they had never openly invaded the rest of the galaxy en masse surprised him. Clearly they had the power to, and Saren firmly believed in the application of power. They had never even openly attacked Citadel Space, for the most part restricting themselves to the occasional raid, but never revealing their presence - any attacks were suspected, not proven. There was never any evidence left.

There was never anything left at all.

It would no doubt be dangerous to try and take a Borg ship, to secure anything useful for the scientists, but Saren had to. It was his job after all. He sighed and punched in the co-ordinates. In one regard, he was fortunate - his researches had indicated that Borg did not attack unless you proved yourself a threat, and that they possessed no ranged combat ability in person. Provided he prevented the Borg from touching him, he should be fine.

He hoped.

Dr Liara T'Soni scanned another ruin on Feros with her old Federation-issue tricorder. While she preferred omni-tools for a considerable amount of her work, Federation science tricorders were pretty handy at their job - even if they did feel a bit unwieldy by comparison to the entirely digital and holographic omni-tool.

She was just beginning a series of expeditions to study the extinction of the Prothean species. While there were few in Citadel Space willing to fund her (as if only being in her early hundreds was actually a good reason to deny her the chance to prove her theories!), the Federation Archaeology Commission had seen the potential value of her work, and agreed to send her on an expedition. They had even paired her with Professor T'Sal of Vulcan, a noted expert in the Federation on Prothean ruins.

T'Sal was a severe looking woman, her short hair cut in an efficient bowl cut. She was cold and bluntly logical, approaching everything analytically.

A lot of Vulcans were supposedly like that, or so Liara had heard - she had found it difficult to imagine a race so emotionless before she had met her first Vulcan. Nonetheless, the Professor was a boon to her work. T'Sal had been a student of more recent archeological treasures until recently, when after a half century studying various Alpha Quadrant civilisations, she had decided to study the Protheans. She had in fact been considering approaching Liara to assist her before the young Asari had endeavoured to contact the Archaeology Commission; her exact words when asked why had been, "your knowledge of Prothean technology and history is impressive".

That vaguely complementary sentence was as close to effusive praise, Liara later realised, as Vulcans ever got, and Liara had since learned to take such vague complements in the spirit they were intended.

She and T'Sal had decided to begin their long work by scanning the ruins of Feros. While it was unlikely that they would learn over-much that was not already common knowledge, it would perhaps prove a good starting point, a base against which to study Prothean architecture and style.

"Fascinating," her Vulcan associate said from across the room. Liara enjoyed the Vulcan's company more than she thought she might - the woman's emotionless nature made her much easier to deal with. "These ruins are incredibly ancient, and yet still, I would judge them to be viable as living spaces – one could move a fully functional colony into this area in only one month. I do not believe I have ever encountered this in any ruins before."

"These are some of the best preserved ruins I've seen," Liara replied, checking her scans again.

"I imagine fifty years of research into the Protheans has given you some fascinating insights," T'Sal noted. It was perhaps unusual for a Vulcan to make small talk in this manner, but Liara knew it wasn't an attempt to make any kind of conversation, but a simple logical deduction being stated for consideration. Vulcans were like that.

"It has," Liara said, confirming T'Sal's hypothesis for her with a soft smile. "But I could spend a millennium studying them and still not learn everything."

"You are fortunate to have that time," T'Sal replied, another logical observation.

"Perhaps so," Liara said. She ran her tricorder over more of the ruins. "Interesting - according to this tricorder, none of this matches the construction of the Citadel."

"Certainly, not all of it would," T'Sal said, looking over at her. "The Citadel is impressive but it is a space station, not a planet-bound city, the construction needs would be considerably different."

"It isn't just the materials that are different," Liara said, now positively perplexed by these scan results. She found herself grateful for the little bulky scanning tool - it had picked up on something she would never have noticed. "This is comparatively easy to scan."

"Your point?" T'Sal asked, looking over at her.

"If you ever try scanning the Citadel, its basic structure is made of materials that your tricorders can't identify," Liara explained. "But this is basically a highly advanced and reinforced concrete-esque mixture."

"You mean that the material of the Citadel is too advanced to have been made by the same people who built this place?" T'Sal said, walking over to Liara and checking her results.

"It would seem that way," Liara said. T'Sal looked over the results and methodically checked them against her own tricorder.

"A logical deduction," she concluded finally. She frowned, the greatest expression of emotion a Vulcan could have. "And it brings up the question: did the Protheans build the Citadel?"

"If they didn't, who did?" Liara asked sceptically. The idea that something more advanced than the Protheans had built the Citadel was... unprecedented.

"Precisely," T'Sal said, the frown furrowing her face. "Precisely."