AN: Alright, here's the real prologue chapter. Got enough feedback and decided to change things up from my original plan. I hope you guys like what I've got in store for this crossover fanfiction.

As far as timelines go for each universe, it goes like this. Star Trek: Voyager wise, directly after Voyager drops out of slipstream warp after Seven of Nine implements Kim's calculations to force the ship back into normal space during the slipstream warp drive test. That's season 5 episode 6. Halo wise, before the second mission to Requiem. Before spartan ops and after Halo 4 for those who are confused. Mass Effect wise? You'll find out eventually.

Edit AN: Since I've noticed that a lot of people read this chapter and then stop right away, I'm going to put the start of the timeline in here. Voyager and the Infinity were shifted into the Mass Effect universe out in the Terminus systems. Way out away from anyone. The date is a number of months before the start of Mass Effect 1. Since I can never find an accurate date for Mass Effect 1, it's just simply the year 2183.

Chapter 1: Dimensional shift

UNSC Infinity

Bridge

The UNSC Infinity was currently traveling through slipspace back to the Sol system for a resupply and refit after a successful shakedown mission dealing with Kig-Yar pirates harassing an outer colony. Captain Thomas Lasky stood near the holotable as the bridge crew completed their assigned tasks without fail and with discipline. 'That crash landing on Requiem several months ago sure did a number on the Infinity's ventral side.' He thought sourly to himself. 'Damn psychotic Forerunner and his ancient hatred for humanity.'

His annoyed thoughts were interrupted as a shudder went through the deck. Brushing the slight tremor off as commonplace, as occasional 'eddies' would occur naturally in the slipstream, Captain Lasky went back to observing his bridge crew at work. A much stronger jolt caused the relatively new captain to stumble a few seconds later. Grabbing the sides of the holotable to steady himself, he called out. "Report!"

"Sir! The slipstream in front of the Infinity is unstable! The readings are off the charts!" The sensor officer shouted out his reply.

"Roland?!"

Appearing in front of Captain Lasky on the holotable in his World War II bomber pilots orange avatar, Roland looked a little shaken as he spoke. "Captain, what I'm seeing isn't pretty. I recommend-" He was interrupted as Captain Lasky was nearly thrown off his feet in the next second. He waited until Captain Lasky had steadied himself. "I recommend we immediately drop out of slipspace before we get caught up in the worst of it."

Captain Lasky didn't hesitate as he answered. "Do it."

Roland brought up a keypad in front of him as he typed in some commands. He technically didn't need to as the ships dedicated AI but did so anyways. Everything went dark as the captain was knocked off his feet in the next moment.

USS Voyager

"Captain? I didn't send any corrections to Seven of Nine." Ensign Kim replied over the comm.

Before Captain Kathryn Janeway could reply, Lieutenant Commander Tuvok urgently spoke up. "Captain. The slipstream exit is reopening behind us."

Captain Janeway looked confused for a brief moment before she commanded as she sat back in her captains chair. "Report. What are we dealing with here?"

"The anomaly appears to be both spatial and temporal in origin. I cautiously recommend we move away from the event horizon." Tuvok diligently answered his commanding officer.

"Chakotay, an anomaly has appeared at the slipstreams exit point. We're moving Voyager away to a safe distance." Captain Janeway called out over the comm to the delta flyer.

"Acknowledged, Captain." Chakotay answered as the delta flyer moved to follow Voyager to a safe distance.

The displaced Federation starship moved out to a safe distance of 50,000 km away from the growing spatial distortion. "Mr Tuvok? What can you tell me about the anomaly?" Captain Janeway asked once the ship had gotten far enough away.

"As the anomaly is spatial and temporal in origin, I deduce that it is a dimensional rift into a different spacetime." Tuvok answered in the clinical blank vulcan tone common for his species. "It has been growing steadily since it first appeared. The rate at which has been increasing exponentially as time has passed." The sensor readings he was reading went wild in the next moment as the hole expanded further. "Captain, the anomaly has grown to a size of 2 km in diameter… something is coming through."

The bow of an immense ship started coming out of the rift. Arcs of electricity seemingly jumping all over its surface. Its running lights were flickering randomly before going out entirely.

"That's a big ship…" Ensign Tom Paris commented in awe as the ship that dwarfed Voyager by a large margin made its way out of the rift.

The rift closed behind the massive ship without issue as it seemed to drift powerlessly. "Captain? The ship appears to be in distress." Tuvok spoke up.

"Explain?"

"Its main power is offline, secondary power offline, emergency power is barely functioning. Life support is online but barely functional." Tuvok seemed stunned for a moment before he continued. "Captain? There is English lettering on the unidentified vessel."

"English?!" Captain Janeway exclaimed as she grabbed the edges of her chair and leaned forward. "Report."

"It reads 'UNSC Infinity' Captain. I am afraid that I am unfamiliar with such an acronym."

Captain Janeway seemed to be at a loss for the meaning of the acronym as well. "Seven, I want a full scan done on that ship before we make any hasty decisions. Lord forbid they take any moves from us to assist as hostile from a ship of that size without knowing anything about their capabilities."

"Affirmative, Captain." Seven of Nine answered.

"Now then, let's find out how much closer we made it home." Captain Janeway mused to herself.

UNSC Infinity

Bridge

What was he doing again? His thoughts were somewhat lucid as his senses were in an utter fog. 'We were on a mission… weren't we? Ah… yes. We had just cleared out some Kig-Yar pirates around the outer colonies on a shakedown run with Roland, eight stridents and two new Anlace frigates. We left two stridents behind for local defense.' Captain Lasky blearily thought as more awareness started to return to him. He became aware of a point of light moving around in his vision in a familiar pattern. Muffled speech started to hit his ears through the incessant ringing that was plaguing his hearing.

"The Captain's coming to." The corpsman said.

"How're his vitals?" Roland asked from the speakers of the holotable.

"No concussion as far as I can tell. Just knocked unconscious from his fall and the event that hit the whole ship."

Captain Lasky sluggishly swiped at the light in his face as he started to sit up. Shaking his head to clear his mind as he looked around the bridge, he called out. "Report!"

"Captain? We're dead in the water for now until we get power back online. I've barely got enough power to run life support as it is. We're blind and have no idea where we are." Roland answered.

"What happened? I thought the Infinity's slipspace drive was supposed to be even more advanced than Covenant drives. What the hell did we hit?"

Roland remained silent for a moment as he used his processing power sparingly. "My best guess Captain is that we hit a ripple in the slipstream. A big one at that. If we had stayed in slipspace any longer we might've lost the Infinity."

"Status on getting our systems back online? I don't want us getting caught with our pants down by any loyalist Covenant ships." Captain Lasky stood shakily as the corpsman helped him back to his feet.

"The power systems are running through a full reset. Once secondary power is back online it won't take long to get main power running again." Roland's avatar reappeared on the holotable along with all the lights coming back on after he said that. "Speaking of which, secondary power just came back online."

"Sensors? What's around us?"

"Alright, let's have a look at where we're at." Roland paused a second later as the sensor readings started coming through. "Captain! We've got an unidentified vessel sitting 50,000 km off our starboard side bow."

"Covenant?"

Roland gestured to the side as he brought up a holographic image of an odd looking ship. "Not as far as I can tell Captain. It's only the size of a small frigate from what I can see." Roland made a confused face for a moment as he walked around the holographic image and focused on the oddly shaped saucer section of the small ship. He stopped and pointed to a highlighted section of the top hull. "Captain, that's English."

Captain Lasky looked closer as Roland enlarged the image for him to see for himself. "USS Voyager? Insurrectionist?"

Roland shrugged. "You got me Captain. That ship is way too different from any designs I've ever seen before."

Captain Lasky scrutinized the holographic image for several more seconds. "What's it doing?"

"Just sitting there as far as I can tell, Captain." Roland brought up a number of different displays with graphs and readouts of what the ships sensors could see. "Captain, I think they're scanning us. Although it's a method of scanning that I've never heard of. These are some strange readings."

"What's the luminary reading? Are they human?" Captain Lasky asked.

Roland made a 'Huh?' face as he looked at the luminary's readings. "Uh, it's not reading anything on that ship. Not a single trace of anything Forerunner or any humans on that ship."

USS Voyager

Bridge

"Seven, what can you tell me about that ship?" Captain Janeway asked.

"It's a warship. The ship is approximately 5.7 km in length. It has hundreds of weapon emplacements across its hull. Mostly projectile based weapons, although there are some laser based ones as well. It has four main magnetic accelerator cannons mounted on its bow. There are also 8 smaller vessels docked within its ventral side." Seven of Nine replied.

"Alright… what about life signs? It has to be a flagship of some kind if it's that large and well armed." Captain Janeway mused to herself at the end.

"Sensors detected approximately 17,000 life signs onboard. Captain, they appear to be human."

"Human? What's the ships current status?" Captain Janeway asked as she scrutinized the blocky ship on the main screen.

"Their secondary power just came back online. Ship systems are starting to return to normal operation." Seven stopped as new sensor readings crossed her station. "Captain, they appear to be scanning us."

Captain Janeway had stood and walked a few steps forward. "Well, better make ourselves and our intentions known at the very least. Hail them."

UNSC Infinity

Bridge

Captain Lasky and Roland were both examining what the Infinity's sensors could currently read on the unknown ship in front of them. While they were doing so the rest of the bridge crew were collecting themselves and returning to their stations. "Sir! We're receiving communication from the unknown! It's not in any encryption type that I've seen before!" The communications officer called out.

Captain Lasky turned back to Roland. "Roland?"

"It's both audio and visual, sir."

"Let's not reveal ourselves until we know what we're dealing with here. Bring up the feed on the holotable." Captain Lasky commanded.

Captain Lasky was then greeted with the face of a brown haired human woman wearing what appeared to be a jumpsuit of some kind. "Well, Roland, at least we know that they're human. Are they receiving us?" A nod from Roland. "Open a channel! Audio only!"

"This is Captain Thomas Lasky of the UNSC Infinity. Identify yourselves."

USS Voyager

Bridge

Captain Janeway turned her head back to Seven of Nine. "Was that a translation?"

"No, Captain. That was standard English."

"At least we don't have to deal with a language barrier at all." Captain Janeway muttered under her breath. "This is Captain Kathryn Janeway of the Federation starship USS Voyager. Do you require any assistance?"

"Federation? Which colonies do you represent?"

"Let me be more specific. The United Federation of Planets is an organization of numerous planetary sovereignties and species."

"Captain?" Tuvok spoke up from his station. Captain Janeway turned her head to look back. "Astrogation just finished its scans. We are not where we are supposed to be."

"Meaning?"

"Our star maps do not match anything in our current surroundings. We are lost." Tuvok replied emotionlessly.

Captain Janeway blinked a couple times as she processed what was said. She closed her eyes as she thought over her next words. "Captain Lasky? You wouldn't happen to know where we currently are, would you?"

UNSC Infinity

Bridge

"Roland? Where'd we end up?"

"Ok… let's see what we've got here." Roland brought up a star map of what was around them. "Uh… Captain? We're not in Kansas anymore." He put the current map alongside another map. "This is where we should be, Captain." Roland pointed to a familiar map near the Sol system. "This, however, is smack dab in the middle of God knows where we are." Roland threw his hands up in frustration.

"How far off from our route did we get?" Captain Lasky asked as he observed the star map in front of him.

"That's just it, Captain. None of these stars match anything in our maps. Oh… some stars are similar, but a vast majority of them are just flat out off and entirely new." Roland gestured around the map of their surroundings as he highlighted different stars here and there. "Whatever we hit in slipspace… it seriously knocked us off track."

"Roland. What are you getting at here?" Captain Lasky asked seriously.

"Well sir, the only thing I can think of is that we got pushed into a different reality altogether by whatever hit us in slipspace." Roland said with a slightly defeated tone. "I'll have to go over our sensor logs in detail once all systems are back up and running to figure this one out."

"Keep this under wraps for now, Roland. I don't want to cause a panic among the crew before we know what the entire situation is." Captain Lasky ordered as he stood back up from the holotable. "The captain of Voyager seemed to be having a similar problem before her last question to us." He straightened out his uniform before he spoke once more. "Open a channel with audio and visual this time."

"Sorry to keep you waiting, Captain. Do your star maps match anything in our current surroundings?" Captain Lasky queried.

"Unfortunately, they do not. I can guess from the tone of your question that yours don't as well." Captain Janeway replied.

Captain Lasky's head dipped slightly before he answered. "We seem to have gotten ourselves into a similar problem then. What was Voyager doing before this happened?"

"We were testing a new drive core. What we refer to as a slipstream warp drive." Captain Lasky and Roland both seemed to mumble 'slipstream' at the same time. "We were experiencing turbulence in the slipstream before we dropped out of warp."

Captain Lasky looked down to Roland to see him standing there in a thinking pose. "This 'slipstream warp drive' as you call it, are you making a full transition into slipspace?"

"Full transition? No, Captain. We are essentially wrapping the ship in a subspace bubble and using that to bypass the speed of light." Captain Janeway looked slightly confused at first.

"Captain? If I can get their sensor data and the calculations that they used I might be able to figure this out." Roland stated.

"Captain Janeway? Our method of FTL is referred to what we call a Shaw-Fujikawa Translight drive, or slipspace drive for short. It opens a wormhole into an extra dimensional space that we call slipstream space. If we can look at your data, we might be able to find out what went wrong for the both of us. Would you be willing to share your sensor data and calculations for your slipstream warp drive?" Captain Lasky questioned.

"I think we can manage that much. I'll do one better and bring the ensign who designed the drive along with us. If you'll invite us onto your ship, that is." Captain Janeway offered.

"I think I can live with that. You may bring security along with you as well. I hope you understand that you'll have an armed escort while on my ship, Captain."

"Understandable, Captain."

"Roland? Direct our guests to the command flight deck." Captain Lasky ordered.

"Aye aye, sir!" Roland saluted as his avatar winked out.

USS Voyager

Bridge

Commander Chakotay and Ensign Kim arrived back onto the bridge mostly through the conversation Captain Janeway was having with Captain Lasky. Once they had finished, Chakotay spoke up. "Captain? I hope you know what you're doing. That ship looks highly militarized."

"The Captain of the Infinity seemed to be a personable person. He has to have incredible discipline for him to be taking our situation like he is." Captain Janeway sighed as she continued. "I see your point though."

"Captain? They've given us a path to a flight deck on the dorsal side of the Infinity. They do not appear to have transporter technology onboard their vessel." Seven of Nine reported.

"Understood. Let's take a shuttle over to the Infinity. No need to reveal all of our capabilities just yet. Ensign Kim? Bring your sensor data and calculations for our slipstream warp drive along. Mr Tuvok? Assemble a security team to stay with the shuttle once we've boarded the Infinity. Captain Lasky seemed trustworthy, but a ship that militarized might have hidden elements within it. I'm not taking any chances with my ship or my crew here." Captain Janeway ordered. "Be ready to beam us back out if any hostilities occur."

"Aye, Captain." Chakotay answered.

USS Voyager 20 minutes later

Shuttle bay

Boarding one of the other shuttles, as the delta flyer was too important to lose, Captain Janeway and her away team boarded the cramped shuttle. "Tight fit would be an understatement here." Ensign Kim commented as the last security officer boarded.

"Well… I'd rather not scare them by simply materializing inside their ship." Captain Janeway called back.

"An appropriate precaution. Their weapons seem primitive, but their overall technological capability and knowledge are still as of yet unknown to us." Tuvok stated.

UNSC Infinity

Command flight deck

The command flight deck hanger doors opened to the black of deep space. The blue atmospheric shield shimmering as it held out the vacuum of the void. "There's the shuttle that other ship sent out to us. Huh. It looks like a smaller version of the main ship. Man, they've gotta be nearly piled on top of each other in there in something that small." One of the flight crew commented as the shuttle came into view.

"Makes you wonder how they move people and supplies off that ship quickly." Another crew member added.

"Captain on deck!" A marine guard called out near the flight deck entrance.

Captain Lasky and a squad of Spartan IV's strode into the bay. One of the spartans being Commander Palmer. "You sure about this Captain? We don't know that much about these people or their intentions yet."

"Easy Palmer. We're both stuck in a similar situation here. And Captain Janeway seemed like the type to care deeply about her crew." Captain Lasky calmly spoke as they stopped.

"If they try anything though, all bets are off… Captain." Commander Palmer said.

The small shuttle broke through the blue barrier and spun around before settling itself down onto the deck. The rear door opened to show the decidedly cramped occupants shifting to move out of their claustrophobic space. Four people dressed in yellow colored jumpsuits stepped out with what looked like sidearms strapped to their waists. One was dark skinned, and upon closer inspection had pointed ears. One of them didn't have a sidearm and appeared to be holding a datapad and some kind of device on his hip. And finally Captain Janeway made her way out of the shuttle in her red uniform.

"Welcome aboard the Infinity, Captain Janeway. We'll be having our meeting in one of the conference rooms. Right this way." Captain Lasky called out to the crew of Voyager.

"Thank you, Captain. You two, stay with the shuttle." Captain Janeway ordered the two security officers with the away team.

UNSC Infinity

Flag Conference room

The spartan guards remained outside of the room as the Voyager crew along with Captain Lasky and Commander Palmer stepped inside. "Let's start by learning a bit more about each other in this situation. We know very little aside from the fact that we're both human. Would you care to enlighten us of your history?"

"Certainly." Captain Janeway offered as she explained the basics of the United Federation of Planets and their mission in general. Captain Lasky and Commander Palmer remained silent as Captain Janeway explained the history of the Federation and her ships current dilemma.

"So… you've been lost out in deep space for about 5 years now?" A nod of confirmation from Janeway. "75 years just to get back home from your original end point. That's one hell of a journey. I can see why you were willing to test out your new slipstream warp drive so readily. Roland? You ready to see what we've got to work with here?"

"Roland?" Captain Janeway asked.

Before Captain Lasky could respond, Roland appeared on the central holotable in his orange avatar. "Hi! I'm Roland. The Infinity's shipboard AI."

"Is Roland fully self aware?" Captain Janeway asked.

"Yup! Fully self aware, ma'am. So… about those calculations?"

"Fascinating." Tuvok commented.

"You can tell them more about yourself later Roland. Right now, we've got more important things to worry about." Captain Lasky ordered the energetic AI.

The asian looking man wearing the yellow jumpsuit stepped forward. "Uh, how do I send you the data?"

"Ah no worries. Just reach your datapad over here and I'll handle it." Roland spoke up as he reached a hand forward.

"Are our computer systems compatible?" Captain Janeway asked.

"We use quantum computing through data crystal technology. Roland? You sure you can work things out?" Captain Lasky questioned.

"Oh I've got this. No need to worry." Roland reached his hand out towards Ensign Kim.

Shrugging, Ensign Kim reached his datapad over towards Roland's outstretched one. Touching the data pad for a brief couple seconds, Roland pulled his hand back holding a holographic representation of Ensign Kim's datapad. "Alright, let's see what we've got here." Roland started swiping his hand over 'his' datapad with a thoughtful face. His expression slowly started shifting to confusion at first before turning into shock. He looked up to the Voyager crew and gave them a look that a parent would to a child that did something really stupid before he looked back to the pad.

"Is something wrong?" Captain Janeway asked.

Roland simply lifted a hand to signal them to be quiet as he kept looking over the data. He let out an explosive sigh as his arms dropped to his sides and his head and shoulders slumped. He 'tossed' the datapad up in the air as it disappeared and a number of different calculations appeared on the holotable behind him. "Let me guess. You guys kept trying to 'push' your way through the turbulence in the slipstream using on the spot corrections?"

"Yes? Did we do something wrong? I worked on the calculations and the drive core myself. My calculations should have worked." Ensign Kim answered

"I'm surprised that you didn't outright destroy your ship with how fast you were trying to go. What you did was build up a quantum bubble in front of your ship in the slipstream. That was the source of your 'turbulence.' You should've dropped back into normal space the instant it started getting rough in there." Roland was pacing around the holotable as he pointed things out to the Voyager crew. "Because you kept trying to get as far as you could, it resulted in that bubble catastrophically bursting right before you dropped out. It sent out a cascade quantum ripple through slipspace that we just so happened to get caught in. It literally shifted our ships into wherever we happen to be right now."

"But… how? I made certain those calculations were correct!" Ensign Kim countered.

Roland's brow furrowed as he looked back at Ensign Kim. "You're new to slipstream space technology. We, however, have been using it for close to 300 years now." Roland groaned out in frustration.

"Easy Roland." Captain Lasky tried to calm the situation down. "I'm sure we can work something out here between our two ships." Captain Lasky shook his head as he thought over the problem they found themselves in. "Captain Janeway? Is it too much to ask for your cooperation in order to get ourselves back to where we belong?"

"It looks like we don't have much of a choice in this situation, Captain." Captain Janeway stated in resignation.

AN: Cliffhanger technique, executed. Trek tropes huzzah! If you're familiar with the star trek verse then you know that they love using cascade reactions and such to explain things away. I know I'm bsing my way through some of this, but hey, it's for entertainment purposes people. If anybody wants to collaborate on this and help me to improve it or add in your own story ideas give me a buzz.

For now, I ride my 18 wheeled stallion.