DISCLAIMER: Warhammer 40,000 and Star Trek are the property of their respective owners, Games Workshop and Paramount. No infringement intended and no profit is made from this story. I only write it because I enjoy doing so.

This is another idea that I had for a 40K/ST crossover. Like Gambit, it'll have the canonically-correct power ratios. Unlike Gambit, I'll delve into how the Imperials got here. However, as I'm in the midst of Gambit and a couple of other 'Skunkworks' projects/ideas, expect this 'fic to be updated very, very sporadically.

Also, I won't be answering reviews for this 'fic in the chapters, as it tends to bloat the word-counts and chapter size. Thank God for PM function.

CHAPTER ONE

The Zelus Probatii smoothly exited the Immaterium, warp vanes trailing and antennas unfurling from the cathedral spire that made up the command tower. The two kilometer-long frigate slowly decelerated, as it cleared the turbulent region of its translation to realspace. It gracefully moved through space, with an air of majesty and power.

It did not realize that it was being watched.

/

Several million kilometers away, the USS Defiant was slowly cruising into the Idran system. Not the first time, and almost certainly not the last, it was a close location to the terminus of the Bajoran wormhole.

Of particular interest was the fact that long-range subspace scans had indicated the presence of a ship-like object that had not been there before. There had been no warp signatures or trails into or out of the system, and preliminary scans indicated the new object was of substantial size; longer than even the Romulan D'deridex class warbirds.

"Dax, what can you tell me about that ship?" Sisko asked.

"Not much sir. It has no warp or subspace signatures, so sign of any mass-lightening technology, no impulse drive emissions, no subspace emissions. Not even a warp core signature. I can tell you that that ship is big, and I mean really big.

"It's longer than a D'deridex, and from what little information the passive sensors are giving me, that ship has some almost wastefully thick armor plating." Dax answered.

"Well old man, looks like we'll have to keep an eye on them for a little while then." Sisko replied.

Several hours later, O'Brien asked what everyone else was wondering.

"Now how do you suppose they got here without anybody noticing?"

"Perhaps they used a cloaking device, like us?" Worf suggested.

"Yes, but why would they then disengage it after traveling?" Sisko countered.

"Maybe the cloak is tied into the drive?" Dax offered.

On it went, until the ship suddenly shook violently.

/

"Helm, confirm course, heading zero-zero-zero, all stop." Shipmaster Marcus Baryk ordered.

The response was almost immediate: "Aye, course confirmed, heading zero-zero-zero, all stop."

The helmsman, or rather helmswoman, Kahl Vought, was probably the most talented of her trade amongst the sectors of the Ultima Segmentum. Other bridge crew present included the vox officer, Carya Laszlo, the ship's commissar, Maya Reinholdt, and Third Enginseer Vex.

"Captain, auguries have detected an attack craft sized ship. I'm having a bit of difficulty resolving type-classification." Laszlo called out.

"Speculation: unknown craft is equipped with holofield analogue. Perhaps tau in origin?" Vex mused.

"I don't care what it's equipped with. Just get me a good look at it, and tell Mabon that his gun crews had better be up!" Baryk bellowed, immediately suspicious of the unknown attack craft.

A chorus of "aye aye!" resounded from the various stations on the bridge. As always, Reinholdt looked on, impassive and watchful, ensuring the crew attended to their duties with alacrity and without question.

The Zelus Probatii's auguries immediately began to focus on the region where the lone attack craft had been detected, whilst the Fury squadron embarked aboard the frigate was prepped and given a datasermon brief.

Either the new arrival would obey and be escorted to where it could be taken aboard and its crew examined and interrogated, or the arrival would become a target, and either the Furies or the watchful and waiting guns of the Zelus would turn it into an expanding cloud of debris.

/

Squadron Commander Caleb Harlen was currently overseeing the prepping of his Fury interceptor. Alongside him, the demisquadron he personnally led was similarly doing so. All ten Furies were launching, though only five could launch from each bay at a time, due to limited space.

As a result, the squadron had to be launched by demisquadron, deploying in 5-craft elements that would eventually link up several hundred kilometers away from the Zelus. It was actually somewhat of an advantage; the squadron was impossible to take out in a single strike during the launch phase of their flight profiles. However, this particular mission was in itself somewhat unusual.

Very rarely did a rogue attack craft require investigation. However, that was mostly due to the rarity of rogue attack craft. It was almost unheard of really.

On the other side of the Zelus, Lieutenant Zane was overseeing the same process for his demisquadron. As the second in command for the squadron, it was Zane's responsibility to muster the other half of the squadron from the frigate.

He was very good at his job.

/

Ten 70-meter long, 200 tonne fighters flew out from the sides of the Zelus Probatii. They angled out, flying straight for several hundred kilometers before circling together into a broadly V-shaped formation. After several minutes of circling, they marshalled up and flew off, away from the frigate.

"Intercept course confirmed. Accelerating to attack speed." Zane voxed over the inter-fighter relays. While other pilots used a combination of hololith tank interfaces, veritably ancient joysticks and throttles, and hololith HUDs, Zane used a Mind Impulse Unit that was supplemented by the hololith tank that he was ingrained into using.

It gave him a considerable advantage in a dogfight situation, the sheer speed with which he could react. It made his already impressive skills as a fighter pilot even more so.

His was the power to bring death, a harbinger of doom.

Just so with the entire squadron.

"Vectoring onto target profile. Confirm weapons free." Another pilot voxed over the 'net.

"All pilots confirm warning shots only, repeat, warning shots ONLY." Harlen called out.

A round of affirmatives and confirmations greeted Harlen's craft.

The ten Furies wheeled around, and fired a burst of lasfire across the bow of the slowly moving rogue fighter.

"Unknown fighter, disengage holofield mechanisms and prepare to be escorted to docking position with the Zelus Probatii." Harlen voxed over at the squadron's target.

/

"Unknown fighter, disengage holofield mechanisms and prepare to be escorted to docking position with the Zelus Probatii."

The bridge crew of the USS Defiant froze.

"Did they just...?" breathed O'Brien.

"Repeat, unknown fighter, disengage holofield mechanisms and prepare to be escorted to docking position with the Zelus Probatii. Heave to, or you will be destroyed."

"Yes. They did." Sisko responded incredulously. "Commander Worf, disengage the cloaking device."

"Aye, captain."

The Defiant's cloaking device disengaged, and the ship reappeared in the visible spectrum. The "fighters", presumably, formed up around the Defiant, ensuring that if it tried to escape it would end up in the gunsights of at least one, and probably more, fighters. Sisko did not intend to escape though; any civilization which could see through cloaking devices would likely be a valuable ally to the Federation.

How wrong he was.

/

Harlen looked over the rogue fighter. It had an unusual design. While the Ryza-pattern Furies that his squadron flew were quite sleek and smooth-lined, particularly compared to the much blockier Calixis and Gothic patterns, this fighter had a flow that was different. It lacked the swept lines of the Fury's swept wings, forward canards, and angled tailplanes and stabilizers.

Its engines were the most perplexing part. There was a reddish glow from two points on the aft section, and a minor mass flow through what was apparently drive apertures. Two pods on either side of the hull had blue, glowing lines forming around them. Perhaps some kind of weapons deployment system?

On Zane's fighter, he too was pondering just how odd this unknown craft was. What was befuddling him, however, was the fact that the fighter's size would require it to have far more mass than his sensors were showing. Further, it should have far more engine power than it did have. Even more unusual was just how slow it was moving. The Furies had repeatedly started to outpace the unusual craft, only to be forced to throttle back.

What in the name of the Emperor are you? he wondered.

/

Captain Benjamin Sisko was feeling distinctly uneasy about the new species that they had likely just met. He was not alone in the feeling; every member of the crew was very suspicious of these possible, though at this point, unlikely, allies.

Several alarming factors had already been found out; these craft possessed a weapons suite that, while uncertain whether it would be able to damage the Defiant to a significant degree, with all ten fighters, it was a foregone conclusion that the Defiant wouldn't win.

Add on to that the fact that it was likely that they had more than just the beam weapons they'd fired, and the very unusual fact that, at the very least, these ten craft were all carried internally by the unknown ship. Who knew if the ship carried even more of these almost certainly formidable escorts?

As they drew closer to the mysterious vessel, it became more and more apparent that it was a warship. The unmistakable forms of weapon ports and turrets, and immense emplacements or gun barrels, dotted the form of the ship. It could be nothing other than an immense battleship, or more likely, a dreadnought.

It sickened several members of the crew, that they had to meet such a warlike race. Still, perhaps they might bring more civilized attitudes to the unknown crew.

No one wanted to give voice to the fact that the Federation was in rather dire need of warlike allies, with the oncoming approach of a possible war with the Dominion.

/

"Captain, we have unknown craft closing rapidly!" Laszlo suddenly bellowed.

"All hands, prepare for combat! Helm, come to heading seven-four-one, ten degree up angle, all ahead half! Gunnery, I want batteries to acquire locks immediately! If it doesn't obey, blow it out of the sky!

"Laszlo, get Harlen on the vox. Inform him that he is to break into demisquads; one demisquad will provide support to the Zelus, the other will keep station around the impounded fighter."

A chorus of affirmatives and "Aye, aye!" resounded. Baryk allowed himself a small moment of pride in the efficiency of his crew and the ship. Obedience without hesitation indeed.

/

"Lieutenant Zane, the Zelus has reported incoming contacts. I'm detaching your demisquad to provide support; I will keep station with the impounded fighter." Harlen voxed over.

"Roger that, Squadron Commander. Angel Squadron, form up on me, full throttle to relayed attack vector." Zane replied.

"Vectors confirmed. Accelerating to full." was the response.

With that, five Furies broke off, hurtling away from the effectively impounded fighter. The remaining five craft of Screamer Squadron reformed and took up station around the unknown craft they had been escorting.

"Unknown craft, you will hold station at your current position. If you do not comply, you will be destroyed. If you attempt to escape, you will be destroyed." Harlen said, directing the transmission at the unknown fighter.

While it had so far not vocally responded, it seemed to understand moderately well. It slowed down, and took up a holding position. Around it, the Furies remained at "anchor".

/

Baryk walked over to the vox station, and took the mike that Laszlo had offered him. He began the process of communicating with the inbound newcomers.

"Unknown ships, you will hold position at your current location, pending escort towards the Zelus Probatii. Comply or be destroyed."

There was no reply, not even an indication that the message was heeded, understood, or even heard. Baryk attempted several times more, before frustration overcame him.

"Unknown ships, you have transgressed Imperial Law. May your souls burn in the Warp forever. Ave Imperator." he walked back over to his station, and voxed Mabon, the gunnery commander of the Zelus Probatii.

"Senior Gunner Mabon, you may fire when ready. Good hunting."

"Aye, captain! All batteries firing."

The deckplates shuddered, as the nigh-upon unimaginable energies were disgorged from the weapons ports of the Zelus's gundecks. Massive fury erupted in space, as immense explosions and plasma bursts swept the void.

The only way for such diminutive ships to survive was by virtue of sheer size; they had very little of it, and the frigate's guns were designed to fire on ships of comparable tonnage.

Not attack craft.

/

Of the three attack craft that had come forth, only one had been downed by the broadsides of the Zelus. Angel Squadron was vectored in to intercept and destroy the remaining fighters.

They stood no chance.

/

"Angel Squadron, break for attack runs. Follow me in." Zane called out over the vox-net that connected the five fighters that composed Angel Squadron. A series of vox-bursts gave the affirmative signal, and Zane pulled his fighter's nose up, bringing it around into a dive.

The turbulent area of space where the Zelus had unleashed her fury was dangerous to fly and fight in or through. Even more dangerous would have been flying in the direct line of fire of the frigate's immense guns. Hence, Angel Squadron had climbed above the system's equator, and leveled out, and was now diving down onto the enemy fighters.

Zane led the fighters, which had moved into a slim diamond formation; a Fury flanked him on either side, while another was riding high aft of his dorsal, and the last was aft and below him. He lined up the gunsights of his Fury, and fired the forward-facing banks of weapons. An array of guns, encompassing lascannon, plasma cannon, and even part of a Vulcan mega-bolter, belched forth fire and fury.

Laser beams, plasma bursts, and bolter shells raked one of the fighters, as it was smashed apart and detonated an unusually small explosion. His wingmen then fired, letting loose with a similar quantity of destructive firepower, taking down the other fighter.

"Zelus Probatii, this is Angel Squadron. Targets destroyed. Requesting new orders." Zane voxed in to the frigate.

"Roger that, Angel Squadron. This is Zelus Probatii; rendezvous with Screamer Squadron and escort impounded fighter to launch decks. Zelus Probatii out."

"Understood, Zelus Probatii. Angel Squadron out."

The five fighters wheeled around, before accelerating towards Harlen and Screamer Squadron.

/

Half an hour later, and the ten-strong squadron was currently circling the Zelus Probatii, whilst the impounded fighter was being docked in place. Baryk himself was present. After all, it was his duty as captain of the ship to keep tabs on all that occurred in the area of Imperial space that he patrolled.

The unknown craft had docked, and bore markings; no doubt a military craft, then, judging by the alpha-numeric analogue that marked its hull. A small airlock on the craft opened up, and several individuals walked out. The first was a dark-skinned, bald man, who seemed rather short to Baryk. The second, an even shorter man, with fairer complexion and a somewhat ruffled appearance.

The third, a woman. Dark hair, light skin, short stature, and some kind of unusual skin pattern along the back of her neck. Without doubt, all three were human, though the woman's tattoos were quite odd, particularly for a presumably military member. The forth, a diminutive, timid looking man.

The last person to exit was an average-height, dark-skinned-

Xeno.

Baryk had never seen such a thing as this. He'd had his fair share of run-ins with eldar and tau, and had even grudgingly accepted their aid on occasion, but he'd never taken on an alien as a crewmember. It was almost certainly a blasphemy of the highest degree!

Still, at least the xeno seemed to defer to the bald human. It did little to mitigate the seriousness of such an act, but did make Baryk feel slightly more at ease.

The group, whose garb reminded Baryk somewhat of the long underwear he'd known some naval officers to keep, approach Baryk and his retinue.

/

Sisko was astounded. The shuttlebay, or perhaps more appropriately, a hangar bay, considering that it could probably have carried an entire fleet of runabouts, was enormous. It had gargantuan blast doors, immense atmosphere containment fields, and monstrously sized equipment that was presumably for handling, storing, and maintaining the escorts that had brought the Defiant in.

Even more perplexing was the crew: almost entirely human! Granted, these humans were tall, most either equal to or exceeding even Worf's great height. All of them appeared at least somewhat familiar with warfare, increasing the Sisko's assumption that this must be a warship.

What was disturbing, however, was the fact that these humans were all pointing weapons at Sisko and his crewmembers that had disembarked. Weapons that Sisko either did not recognize, or could only think of as primitive projectile weapons.

These weapons were blocky, utilitarian, and functional. There was no aesthetic grace, no sleekness to them. It shed light on their purpose.

They were tools for killing, nothing more.

Sisko stopped several meters in front of the imposing figure of the man who was presumably in charge. He extended his hand, and spoke.

"I am Captain Benjamin Sisko, of the United Federation of Planets. I would like to welcome you here, and hope that we can open up diplomatic relations with your people."

/

Baryk simply stared at the man. United Federation of Planets? Was he mad? Did he not know that the Imperium of Man ruled ascendant over the entire galaxy?

"Captain Sisko, I'm afraid you misunderstand. You and your fighter are being impounded for trespassing Imperial territory. You were not brought aboard to open up diplomatic relations with whatever faithless institution you represent."

"Fighter? The USS Defiant is an escort ship, not a fighter. I don't understand, though, why you would impound us. The Idran system is, to my knowledge, Dominion territory. I've never even heard of an Imperial anything.

"Though, I'm curious, what is your name? I've introduced myself, and it would be polite of you to reciprocate the gesture."

"Escort? Idran? Dominion? Politeness?" Baryk laughed. "That's the most ridiculous string of statements I've ever heard. The Zelus is an escort, not that odd little fighter of yours! This system is designated as J9-744B, and is part of the Rola subsector. This Dominion, if they claim this system as theirs, have quite the wrong impression.

"J9-744B belongs to the Imperium of Man. It always has, and always will, belong to Mankind. As for 'politeness', well, I suppose I'll humor you, seeing as you've given me a good laugh. I am Shipmaster Marcus Baryk, of the frigate Zelus Probatii."

"This ship is an escort? But that's impossible. It's two kilometers long, larger than any battleship I've ever seen!" the rumpled man said.

"The Zelus, larger than a battleship? Have you lost your wits, man? Any idiot versed in naval operations knows that an Imperial battleship is an 8 kilometer long warship. I don't know where you people are from, but I can tell you this!

"The Imperium does not look kindly on trespassers! Since most of you are human, you will be given some leniency. Though I'm curious, just how big is this 'Federation' of yours?" Baryk replied.

"The Federation encompasses one hundred fifty full member worlds, with the seat of government on Earth." the timid one replied.

Baryk had been turning away to give out orders, when he froze.

"What did you say?" he asked, voice hardly above a whisper, as he slowly turned around.

"That the Federation enco-"

"No, where the government of this Federation is! Where did you say it resided?" Baryk yelled, interrupting the timid individual.

"On Earth, of course. Where else would it be?"

Baryk whirled around, snapped his fingers, and pointed at one of the armsmen.

"You! Pass these instructions to the bridge, 'Take course for the system's edge, prepare for Warp translation'.

"You!" he said, pointing at another armsman, "Inform the Navigator that he is to plot course for Holy Terra!"

"Aye, Captain!"

The two armsmen ran off.

"Set course for Earth? But that's impossible! Such a journey would take decades to cover!" the rumpled man exclaimed.

"You should keep your mouth shut, you fool, as you've already demonstrated your total incompetence in naval operations. With luck, and good currents, then we should be there within six years realspace-time."

/

The crew Sisko had brought with him were all looking at this man, Baryk, with astonishment. Only six years to cover more than seventy thousand lightyears! It was almost unthinkable!

Sisko considered his options; it was likely that Baryk would be adamant in heading to Earth. For what reason, he didn't know. However, he might be able to get on Baryk's good side by pointing out that there was a wormhole that would vastly shorten the journey.

"Captain Baryk," Sisko began.

"What is it now?" Baryk snapped.

"I know of a route that will be much faster."

Baryk looked at him, with some interest.

"Continue," Baryk said, somewhat warily in Sisko's opinion.

"There is a spatial anomaly known as a wormhole; it facilitates travel between the Federation's territories in the Alpha Quadrant and this system in the Gamma Quadrant. It will take mere seconds, minutes at most, to traverse the seventy thousand lightyears between the two wormhole termini." Sisko finished.

"How interesting. And just where is this wormhole?"

"It is approximately four lightyears from this system."

"Direction?"

Sisko looked towards Dax, who rattled off a series of coordinates and headings. Baryk simply looked rather confused by the information. He then looked thoughtful, before speaking again.

"It would appear that you will be required on the bridge then. I'm certain that you are aware of the consequences of attempting anything, untoward, whilst on the command deck of the Zelus?" Baryk said.

Sisko felt a chill run up his spine, as he realized that Baryk would have no qualms with simply killing Sisko and his crew. He nodded, acknowledging that he understood what Baryk had implied.

"Excellent. Then follow me. And keep your comments to yourself, as I suffer from being remarkably short tempered when dealing with incompetent fools."

/

Baryk brought these "Federationers" up on the bridge of his frigate.

"Laszlo, what is Delta Wing's status?" he said, as he walked towards his command throne.

"Delta Wing is currently docked and waiting for debrief datasermon. D-99 is doing drills in the lower hangars, and maintaining their aircraft. All personnel are ready for Warp translation."

"Excellent. You," Baryk said, snapping his fingers and pointing at the only woman of the Federation party. "What is your name?"

"Lieutenant Commander Jadzia Dax. Helmsman of the USS Defiant."

Baryk's expression conveyed his displeasure quite well.

"I did not ask for rank, name, and position. I asked only for your name. You have no rank whilst aboard my ship. That is Lieutenant Kahl Vought. You will assist her with aligning the Zelus Probatii towards this 'wormhole'."

Dax nodded, and walked over to Vought's station, beginning to converse and exchange helm control methods. Several hours later, they were at the point that Baryk had selected for the Warp translation.

"All hands, prepare for Warp translation." Laszlo announced over the inter-ship vox.

Blast doors closed over the bridge windows, and a great hum could be heard, emanating from somewhere far below. On the exterior, a massive, multicolored rift had formed in front of the Zelus Probatii.

It lashed the frigate with etheric lightning, though it did no damage. The frigate then slid into the Immaterium, and was swallowed by the rift. There was no trace left, other than the debris clouds of three strange, and weak, fighters.

/

And that's it! The entrance of an Imperial frigate into the Dominion War will change the strategic and tactical landscape dramatically, and, with the inclusion of Detachment D-99 (formerly the 99th Elysian Drop Troops Regiment), there are some 300 Imperial Guardsman ready for combat!