A/N: Hey guys thanks for reading. This here is my Halo X Mass Effect Crossover. I want people to know that I take a few liberties with the dialogue of the Mass Effect games. Any constructive criticisms are greatly appreciated. I'm always looking to expand my writing and I love to receive feedback.

I do not own any characters or rights to either of the Halo or Mass Effect games nor do I claim to.

2578 At an Unknown Installation

"Ariel just tell me plainly, what the hell am I looking at?"

"Marcus. . . I have no idea."

Marcus raised an eyebrow at that. Ariel was a Class 4 'Smart A.I.' developed for cyber warfare and as a personal combat A.I. for him. Based on ancient Forerunner technology Ariel did not simply get stumped like this.

"Can you give me anything?" He asked.

"Only that whatever it is it, it's made of the same materials as the Forerunner installation encountered by the Master Chief."

"I'm sensing a but."

"But," Ariel continued, "This is most defiantly not a Forerunner installation."

"How can you tell?" Marcus asked intrigued.

"For one thing the energy readings are off the charts." A graph appeared in front of his heads up display showing a multitude of different level of radiation. "And secondly there seems to be some sort of gravimetric anomaly at the center of the installation."

"What kind of gravimetric anomaly?"

Suddenly Ariel's avatar appeared before him. The small holographic emitter embedded in his MOLNIR Mk X armor projected her in front of him. He usually used the emitter to display topographical maps in front of him on the battle field, but sometimes Ariel used it to project herself. She had a beautifully angled face with sharp features. She wore a simple white dress one that reminded Marcus of his sister back home, many years ago, but her most striking feature was that she had chosen to portray herself with a pair of magnificent wings.

"Whatever it is it's throwing off all our scans, I can't even tell you how big the damn thing is because of the mass fluctuations." She said.

Marcus sighed. It wasn't the first time he would be performing an op with limited Intel it wouldn't be the last either. He turned and looked across the command bridge. Where normally seven different Spartans would sit were nothing but a bunch of empty chairs. The frigate Pride of Vengeance was one of the new class of UNSC Spartan support frigates. March 3, 2553 might have marked the end of the Great War, but the Jiralhanae had stubbornly refused to give up. Without the San 'Shyuum's leadership the Brutes devolved into their old clan structures, fighting amongst themselves and against humanity. Even thirty years later the Spartans were still the UNSC's best answer to the sheer physical might of the Jiralhanae.

Thirty years of reconstruction was not enough the completely erase all the scars of the Great War, but the UNSC had sure done its best. The UNSC fleet was now filled with larger and newer ships, new technologies taken from the Forerunner's gave rise to more powerful weapons, and with the Sangheili Civil War ended humanity now had some major allies.

The UNSC determined six years ago that it needed to give its Spartan team's greater tactical flexibility. The Pride of Vengeance and the other Keys Class Frigates were the result of that line of thinking. The Pride and the other support ships were advanced UNSC frigates that combined designs from both the Forerunners and the Covenant. The Pride was equipped with one of the new MAC-2 guns, the new design featured an over-under style barrel, rather than the traditional single barrel. Smaller in scale than the traditional MAC guns of the Great War the new MAC-2B's round only weighed in at three hundred sixty tons and each barrel fired three rounds at a time, and each round impacted with the force of a ninety kiloton bomb. Each barrel had a sixty second recycling period if the shots were staggered that meant the Pride could put a devastating amount of fire power into space. She also featured a total of fourteen Archer Pod's split between bother of her flanks, a pair of plasma torpedo tubes, and six plasma beam lances as her secondary weapons. She had a hanger bay that supported two drop ships, a pair of Warthogs, a Scorpion tank, and six HEV tubes for orbital insertion, most importantly an entire deck that was dedicated to care and maintenance of the Spartans and their armor. Protecting it all was nearly two meters of Titanium-A and Forerunner alloy along with latest version of energy shields the UNSC could provide. Combine that with the Forerunner clocking device and the Pride of Vengeance was one of the toughest ships in the UNSC fleet. Armed and armored to the teeth the Pride could get in drop of her Spartans and get out before anyone had a clue.

The Pride is basically a frigate designed to run by a minimal crew, between the eight Spartans that were supposed to be stationed on board, the A.I. Ariel, and the hundred or so Huragok onboard the Pride had more than enough man power. The only problem was that right now Marcus was the only Spartan on board.

Spartan Team Witch Fire had recently engaged the Jiralhanae at New Harvest. In order to save the system they had used their old support frigate as a battering ram, slamming it into a Jiralhanae cruiser and firing the MAC gun at point black range. It wasn't exactly an elegant strategy but it had worked. The Spartans managed to evacuate, however Spartan 708 William also known as W-6 had stayed onboard to make sure that the MAC gun fired properly. Marcus was to join Witch Fire as a covert ops specialist, he was slated to replace their lost brother as W-6 and along the way he was to bring them their newly minted support frigate and A.I.

They had been in slipspace for several days when Ariel suddenly detected an anomaly in slipspace and had been forced to make an emergency transition. Advances in slipspace technology meant that Marcus didn't have to spend the trip frozen in cryo sleep. The installation if you could call it that was massive, as advanced as the Pride is, even for a frigate, she still only measures eight hundred meters in length, but this installation could easily have been over a hundred kilometers in length. Whatever the installation was doing to generate that gravimetric anomaly was powerful enough to distort slipspace which is what had caused Ariel to transition back to normal space.

Marcus had sent reports to HIGHCOM. They had responded by ordering him to use the Pride's sensors and gather as much information as possible and to send it back then continue on the New Harvest and join Witch Fire. A science team would be sent in later to investigate.

Marcus glanced at the data pad in his hand and reread HIGHCOM's orders, "Alright then, Ariel. Let's get this done."

"Yes Marcus." Ariel fired up the ship's engines and they began to approach the installation.

"Nice and easy Ariel. Let's take this slow." Marcus ordered.

"Yes, Spartan." As Ariel slowed their approach to the installation, Marcus tried to make sense of what he was seeing. It was shaped like a giant tuning fork, the two arms made up at least three quarters of the structure's length. Where they joined there was some kind of energy field and it looked to be held in place by some spinning rings of some sort. Whatever the energy field was, it was so powerful he could see the distortions in space with his naked eye, it was almost neon blue.

"Are you getting anything?" He asked.

"Some." She replied "I think I can adjust our sensors to compensate for the distortions being caused, but if we want to get any relevant data we're going to have to get closer."

"Where are we now in relation to the object?"

"We are currently holding station at five hundred kilometers from the installation."

"And how close would we need to be in order for you to be able to pick anything up?"

"At least half that distance."

Marcus sighed "Alright Ariel bring us in closer, but make sure the shields are up before we move, if this thing's got any surprises I don't want to be caught with my pants down."

"Of course." She replied.

The Pride slowly began moving forward again almost inching its way closer to the massive construct. Suddenly warning claxon's began ringing out on the bridge.

"Marcus, We're being targeted!" Ariel shouted.

"Get us out of here now!"

Suddenly what looked like a bolt of blue lightning struck the Pride; her shields flared but held. "We're hit!"

On the bridge terminals shorted and exploded as power surged through the ship. The main terminal in front of Marcus suddenly blew up pelting him with shrapnel. If he hadn't been wearing his MOLNIR armor he would have been cut to ribbons. "Ariel!" He shouted.

"Attempting to compensate through non critical systems!"

"Deploy a beacon! We have to warn the UNSC to stay way!"

"Launching. We have a problem Marcus."

"What's wrong?"

"The power surge is feeding energy directly into the slipspace capacitors. The slipspace generator's powering up and I have no way to control it! Without slipspace calculations there's no way to tell where we'll end up!"

"Is there any way to divert the power?"

"All the systems are overloading! There's nowhere for the power to go."

"Then I guess I better strap in." Marcus dashed to a crash seat and slammed himself down. A pair of bars came down over him and locked him in place.

"The wave form is generating. Hang on Marcus! This is going to be rough!"

March 3, 2187 Exodus Cluster / Utopia System

"Marcus!"

Marcus's head snapped up. "What happened?" Whatever had happened to the Pride had knocked him out cold. He tasted copper in his mouth.

"We experienced some form of acceleration shift and the inertial compensators couldn't keep up. You experienced almost twenty gees for a period of five point three two minutes."

Marcus's mind reeled, "What about the Huragok?" The Huragok engineers were essential to the function of the ship. He had made it through the acceleration shift mostly because of his MOLNIR armor and his augments.

Ariel's tone took on a somber note, "Thirty-two didn't survive. A number of the others have been injured to various degrees. I've ordered those still alive and in good health to help the injured and to take care of their dead."

Marcus hung his head. The Huragok were simple and uncomplicated, if you had their trust they would do whatever it is you asked of them, even if it meant their death, but to have so many die without cause saddened him. "What caused the acceleration shift?"

"Unknown. You know I really hate not knowing anything. Today is just not my day."

Marcus smiled, "You're doing fine Ariel. Where are we?"

"Scanning. We exited slipspace in an unknown class G system with five planets. One of the planets seems habitable. Aside from that there's not much else I can tell you. I can't seem to find any known UNSC constellations."

Marcus thought for a moment. "What's the ship status?" He asked for a moment as he got out of the crash seat.

"That I can answer for you. The power surge blew circuits and terminals all over the ship. The weapon systems, shields, and reactors are all down. Engines are at fifteen percent. What power we do have right now are the emergency back-ups for life support. The Shaw-Fujikawa generator seems to be mostly intact, but the capacitors that allow the formation of the waveform are all blown there's no way we can go to slipspace until we can repair them. Most of the external systems are down and it seems there might be some damage to the port side plasma torpedo launcher. I won't know more until the Huragok can investigate."

"What about the Forerunner cloaking system?"

"There's some good news. That's the only system I'm showing one hundred percent functionality."

"Good get the Huragok started on the generators and life support. As soon as we have power cloak the ship I don't want anyone sneaking up on us. In the meantime I'm heading down to medical to get checked out. Alert me as soon as you find anything."

"Affirmative."

"Marcus."

"Yes Ariel." Marcus's eyes opened as soon as he heard the A.I. call.

"I have something you need to see."

"I'll look at it in the opps room. Give me a moment."

"Of course. See you there."

Ariel's form faded from view as Marcus stood up. Apparently the acceleration shift that he had experienced had been a little harder on him than he had thought. He had been put under to have some internal bleeding stopped. As he stood, he stretched to make sure everything was alright and that nothing would inhibit his movement.

When he entered the opps room he saw Ariel standing next to holo projector. She turned and looked at him and smiled as she looked at him. "Good to see you up." She said.

"Good to be up. Give me an update on the ship status."

"Luckily the reactors weren't that badly damaged. Their control systems were fried like everything else on board the ship, but their built-in safeties auto shutdown the reactors to prevent a meltdown. Those are parts we keep on hand in case of catastrophic damage, the Huragok should have them replaced momentarily." As she finished a faint hum reverberated throughout the ship. The emergency lights flicked off as main power was restored. "Engaging the cloak field."

"Good. What was it you wanted to show me?"

"This." She turned and looked at the holo projector as it came to life. "I just managed to pick up this distress signal."

Human soldiers were fighting, against what he couldn't tell. It must be a helmet cam based on the view. Suddenly a Gunny Sergeant ran up and pushed the helmet down.

"Get down!" she yelled. She turned and fired off a couple of rounds before ducking behind cover.

The camera panned around. Marcus saw fire from what looked like some form of directed energy weapon. Suddenly a corporal ran up to the camera.

"We are under attack. We are taking heavy casualties! I repeat taking heavy casualties! We can't . . . argh! –eed evac. They came out of nowhere! We need –!"The corporal slumped forward with a blank look on his face having been shot in the back.

Suddenly a loud buzzing cut off all other sound. The soldier on the holo suddenly glanced up, a look of shock and terror on his face. Off in the distance was a massive vessel, it had smooth organic lines, similar to Covenant design. Only where Covenant ships looked like a wale this looked more like a cephalopod.

Suddenly the signal turned to static. "There's nothing else. Everything just cut's out. There's some kind of jamming signal blocking communications."

"Those weren't UNSC personnel, they weren't wearing standard issue UNSC equipment." Marcus stated.

"No they weren't." Ariel agreed. "Those weren't plasma discharges either, which means it's probably not the Covenant, also the signal was devoid of all standard UNSC protocols. Whoever's down there they're not UNSC and we don't know who they're fighting."

"Where did the signal originate from?"

"The second planet in this system, where there seems to be a sizable colony. I would have spotted it sooner if the ship weren't half blind and deaf."

"Are there any other ships in the system?"

"As far as I can tell, no. We're all that's here."

"Prep a pelican I'm going down."

"Can't Spartan, the Pelicans are fine they came through our transition alright, but the launch rails that move them into position are all fried. We can open the hanger doors but it does us little good if we can't get the birds lined up."

"What about the HEV pods? Can we do an orbital insertion?"

"That's a no go too. The pods' internal computers are scrambled without them you'd hit the surface at terminal velocity, Not even you can survive that. Unless you plan on jumping out the air lock there's no way we can get to the surface."

Ariel saw Marcus's head pick up at her last comment. He turned to look at her with a sly grin spread across his face.

"Oh no. You're crazy you know that?" She said.

"No I just get bored easily, besides I'm a Spartan." He said simply.

"Go get suited up, and head to the hanger. I need to have the Huragok modify a couple pieces of equipment before you can jump."

Alex Shepard stood on the bridge of the Normandy listening to the two soldiers in front of her talk.

"I hate that guy."

"Nihlus gave you a compliment, so you hate him?" Kaiden raised his eyebrow at Joker.

"You remember to zip up your jump suit coming out of the bathroom, that's good. I just jumped us halfway across the galaxy and hit a target the size of pinhead, so that's incredible." Joker retorted, "Besides Specters are trouble, I don't like having him on board. Call me paranoid."

"You're paranoid. The council helped fund this project they have a right to send someone to check on their investment."

"Yeah. That is the official story." You could practically see the quotation marks the sarcasm was so thick. "But only an idiot believes the official story."

Kaiden raised an eyebrow. "What do you think commander?"

Alex thought for a moment. She had been told the same thing about the Council Specter as everyone else, she had no reason to doubt Nihlus or Captain Anderson, but something in her gut told her otherwise. Ever since Akuze she learned to trust her gut. "You don't send Specters on shake-down runs." She finally agreed.

"Joker status report." Anderson called over the com.

"Just cleared the mass relay captain."

"Good. Find a com buoy and link us into the network. I want reports relayed back to Alliance brass before we reach Eden Prime."

"Aye, aye Sir. Better brace yourself sir. I think Nihlus is heading your way."

The captain's voice suddenly became serious, "He's already here, Lieutenant. Tell the Commander to meet me in the com room for a debriefing." With that the Captain cut the com.

"You get that Commander?" He asked looking over his shoulder.

"Great. You piss the Captain off and I'm the one who has to deal with him."

"Don't blame me he's always like that." Joke defended.

"Only when he's talking to you, Joker." Kaiden retorted.

Alex turned and began walking to the CIC. She couldn't help but marvel at the Normandy. She was the most advanced ship in the Alliance Fleet. The first ever ship to incorporate both human and Turian designs. The Normandy was fast, agile, and almost impossible to detect, just the way Shepard like to operate.

The CIC was a bustle of activity. She could see Navigator Presley hard at work at his terminal. He was always the serious one. As she continued to make her way back to the com room she could see Jenkins talking with Dr. Chakwas. As she passed she could hear snippets of their conversation.

"I hope we get deployed soon." She heard Jenkins say. Shepard frowned at that. If she didn't have to meet the Captain in the com room she would have stopped and talked to him about that. Jenkins was young and eager which isn't a bad thing, but being reckless can get you and your teammates killed. She resolved to do that as soon as possible.

As Shepard entered the com room she saw Nihlus standing there alone, a picture of Eden Prime was displayed before him on the holo terminal. He turned as she entered.

"Ah Commander I was hoping you'd get here first, it'll give us a chance to talk." The sub vocals in his voice gave nothing away.

"What about?" She asked.

"I'm interested in this world we're going to, Eden Prime. I've head it's quite beautiful."

"I've never been there." Shepard admitted. She had grown up on Earth, she had never seen nor set foot on another planet until she had joined the Alliance.

"But you know of it." He insisted, "It's become something of a symbol of your people hasn't it? Proof that humanity can not only establish colonies across the galaxy but also protect them, but how safe is it really?"

Something was off about Nihlus's comment. "Is there something you need to tell me?" she asked.

That's when the captain came in. "I think it's time we told the Commander what's really going on."

Nihlus nodded his agreement, "This mission is far more than a simple shake-down run."

"I already figured that out."

The Captain smiled inwardly at Shepard, Can't fool her, he thought. "We're making a covert pickup on Eden Prime. That's why we needed the stealth systems operational."

"There must be a reason you didn't tell me sir."

The Captain nodded. "This comes straight from the top, information on a strictly need-to know basis. A research team on Eden Prime uncovered some kind of beacon. It was Prothean."

Shepard's eyes widened in understanding. The Prothean's were a hyper advanced race that existed fifty thousand years ago. The last store of Prothean knowledge that humanity had discovered had jumped their technology forward two hundred years.

"Obviously this goes beyond mere human interests' commander, this could affect every species in council space." Nihlus said.

Shepard nodded her understanding, "Something tells me that not the only reason you're here though."

Nihlus smiled, or at least he did what Turains called a smile," That's correct Commander, I'm also hear to evaluate you. I've read the reports about you. N7 commendation top of your class, a brilliant technical expert and sniper, and also the only one of your unit to survive Akuze. The Specters can use someone like you, which is why I put your name forward as a candidate."

Shepard raised an eyebrow at that last comment, "You put my name forward?"

"That's right commander. I don't care that you're human, I only care that you can get the job done."

Shepard smiled at that. It was refreshing to meet a turian that was willing to be practical. "I assume the Alliance is alright with this sir?" She asked looking at Anderson.

"The Alliance needs this, Commander. We want a bigger role in shaping interstellar policy. We want more say with the Citadel Council. The Specters represent the Council's power and authority. If they accept a human into their ranks, it'll show how far humanity has come."

Shepard looked at Nihlus, "What do I need to do."

"Eden Prime will be the first of several missions together. I need to see your skills for myself commander."

Anderson nodded "You'll be in charge of the ground team. Nihlus will accompany you. Secure the beacon and get it onto the ship ASAP."

"Understood Captain."

"Anderson nodded, "We should be-."

"Captain!"

Anderson frowned. Joker may get under his skin but he would never interrupt the captain during debriefing unless it was necessary. "What's wrong Joker?"

"Emergency transmission from Eden Prime, sir. You're going to want to see this."

"On screen."

What followed was the same transmit ion that Marcus had seen a few moments earlier. When the massive ship was shown Alex felt her gut clench at the sight, whatever it was made her uneasy. Suddenly the feed went dead.

"Everything cut's out after that no come traffic at all."

The captain narrowed his eyes. "Reverse and hold at thirty eight point five." The monstrous ship once again appeared on the display. In a rare sign of agitation Nihlus clacked his mandibles together.

"Status report Joker."

"We're seventeen minutes out and I'm not reading any other ships in the area."

"Alright Joker. Take us in fast and quite." Anderson looked over at Nihlus. "This mission just got a lot more complicated."

"A small strike team can move quickly. It'll be our best chance to secure the beacon."

"Agreed. Commander tell Alenko and Jenkins to suit up. You're going in."