First thing of note, I don't own Halo or Mass Effect. That goes to 343i and Bioware respectively. Second thing, first time writing the Mass Effect Universe so please be nice.

Also, the UNSC will be using Element Zero to a degree. Mostly in the fact that some of the ground vehicles use it, but warships particularly anything bigger than Light Cruisers which are 1,250 meters long use a combination of Element Zero Drives and Fusion Drives for propulsion instead of straight Element Zero Drives.

Now I will be tweaking the capabilities of the Citadel Races so that way the UNSC doesn't stomp them hilariously.

Book I: THE SHANXI AFFAIR

0230 Hours, February 3rd, 2625 (Military Calendar)

In unnamed system at Shanxi's sister relay

Onboard UNSC London

The London was old ship, the last of the Paris class Heavy Frigates. She had been built and commissioned in the year 2551 and by some miracle had survived the Human-Covenant War. Now here she was on her last jaunt before she was slated to be decommissioned and scrapped.

Not that Lieutenant Commander Iago Blower cared. As ancient and archaic that the London was, she was his first command and thus was in love. That said, he wasn't happy about his assignment. They were out babysitting a science ship that was activating Shanxi's sister Mass Relay, it was boring as hell.

Then it all changed. "Captain, we got fourteen unidentified ships inbound. Bearing 045 degrees relative, 005 degrees inclination, range 1,825,600 kilometers and whoa! Contacts just went FTL in Real Space! Closing, five light seconds, four light-seconds, three light-seconds, two light seconds, unknowns have dropped out of FTL and are closing rapidly, range 250,000 kilometers. Scans indicate that they are using nothing but Element Zero drives, even on the biggest ship." The ship's AI, Igla said somewhat concerned.

That's not a good sign. Iago thought. "Bring the ship to TAC CON Alpha 3! Broadcast a standard warning, they get closer than 150,000 kilometers then they are to be considered hostile. Signal the Ellen Anders, tell them to have their slipspace drive spooled up and ready to go." He ordered.

"Yessir!" Igla said.

"Sir, the Anders has received our message and is spooling up her slipspace drive. They will jump the moment the shooting starts." Comms said.

"Roger Sparks." Iago replied.

"Inferno missile pods are hot, point-defense pulse laser cannons coming online, CIWS spun up and hot, MAC and secondary guns are charging at their maximum rate. ECM system is on but not engaged, decoys ready to launch, and Omni-directional hardlight barrier primed!" Ops reported.

"Reactors at fifty percent output, ready to go to one hundred percent on demand. Emergency thrusters armed and ready to fire on command." The helmsman replied.

Iago nodded, good the London was ready just in case things went south. Which considering how these unknowns were approaching them it was highly likely.

He glanced at the holographic screen, the range was now 200,000 kilometers. "Ship types?" Iago asked.

"Unknown sir. Biggest ship is about 950 meters in length, with four ships being roughly 720 meters in length, there are three ships that are 475 meters, and the last six ships are absolutely tiny at 150 meters long." Igla said.

"What's the range and what does their formation indicate?" Iago asked.

"Roughly 160,-" Igla began before Ops interrupted him.

"Sir! I am detecting Superluminal targeting sensors locking on! Based on the frequency I say it's Forerunner based!" Ops said.

"Action stations! Reactors to one hundred percent! Alert the Anders tell them bug out straight to Shanxi and tell them to declare a probable WINTER CONTINGENCY alert. Helm, initiate the Cole Protocol, purge our navigational database! Ops, activate the Hardlight barrier and go full defensive ECM! Igla, find me a target!" Iago roared and the atmosphere on the bridge turned to ice. The last time the WINTER CONTINGENCY had been declared was in 2555 when the Storm Covenant had struck a UNSC Colony World. The last time the Cole Protocol had been enacted was in 2557 again thanks to the Storm Covenant. The fact that it was being declared again, just a mere twenty years after the discovery of Prothean Ruins on Mars after a dust storm and on the eve of the centennial anniversary of the start of the absolute worst war in human history? As CINC-Navy Thomas Lasky would say "Here we go again."

The London's aging reactors came to life, a thundering growl that was more felt than heard. The frigate swung around to face the oncoming threat, her engine block aglow with anectic helium-four. While projected from an emitter in her bow appeared a thin yet incredibly durable barrier of blue colored hardlight that was set at an angle while her ECM went to full power, throwing out a wall of defensive ECM. But the ECM system was one of the systems that hadn't been touched in the London's long career, mainly because ECM systems that could spoof Superluminal sensors did exist they also required large amounts of power, which unfortunately was something that the London's ancient Mark VIII D-He3 Fusion Reactors just couldn't provide.

"Sir, the Ellen Anders hasn't finished spooling up her drive. They need twenty minutes before they can go!" Sparks said.

"Shit! Tell them to use the Mass Relay!" Iago barked.

"Enemies firing!" Ops shouted.

The Omni-Directional Hardlight Barrier, a normal cool blue, flashed angrily within moments as numerous slugs in the seventy and fifty kilogram range accelerated to velocities of 25,000 and 20,000 kilometers per second respectively fired from the lead alien ship and her four smaller attendants smashed into the barrier with 5.22 and 2.39 megatons of TNT respectively. The frigate shuddered as a beating that would cripple her in moments was unloaded into her hardlight barrier, some of the kinetic force bleeding into the hull.

"Hardlight barrier at eighty percent capacity and falling! Other ships getting involved! Enemy has high rate of fire! Range to hostile fleet 155,000 kilometers, bearing damn well dead on, inclination two degrees!" Igla said, as the second smallest of the unknowns contributed their own fire, sending thirty-five kilogram slugs hurtling towards the London at 15,500 kilometers per second, impacting the hardlight barrier with the force of just over a megaton of destructive force.

"Give it back to them damnit! Select one of the bastards and fire the MAC!" Iago roared.

"Enemy Romeo-Two locked on! Firing!" Weps said as the Hardlight barrier dropped for a fraction of a second allowing the London's Light-Coil MAC gun to discharge it's five-meter diameter, blunt nosed, 100-ton ferrous metal jacketed depleted uranium cored slug at a velocity of 12,750 kilometers per second, with the destructive power of 1.94-gigatons of TNT behind it.

It took the round twice the time to reach its target compared to the Mass Effect fired rounds that were pelting the Hardlight Barrier of the London. But it's effects were much more dramatic. The alien ship designated Romeo-Two stood no chance, with a brief but violent purple-blue flash the round interacted with the ship's Kinetic Barriers and completely overloaded them, blowing their generators as they tried to stop the round. The shell, now somewhat deformed and it's velocity greatly reduced to only about five thousand kilometers per second then bisected the ship from stem to stern, the ship appearing to ripple as hundreds of megatons of TNT in kinetic energy were transferred to the hull. Then with a brief but violent dark blue black flash the Eezero core blew and reduced most of the rapidly expanding debris field to it's component atoms.

The hostile fleet immediately scattered. Their engine blocks erupting into life with blue antiproton fire and rapidly began to close the range against the lone Heavy Frigate, their guns blazing. However, the London's Omni-directional Hardlight barrier held firm against the onslaught.

"That's a hard kill! Five minutes until we can do that again!" Weps whooped gleefully as a resounding cheer swept across the bridge as the marker for Romeo-Two winked out of existence.

"Hostiles trying to flank! Judging by speed they are enemy destroyer and frigate analogues. Two groups are angling for our flanks, each group has two frigates and one destroyer. The last group is going for the Mass Relay! The enemy Cruiser analogues led by that Battleship are trying to get us in a pincer! Enemy Battleship going high, one enemy cruiser coming at us dead on, and the last two cruisers are going below us!" Igla said.

"Alright! Secondary battery engage Romeos six through twelve. Fire Inferno Missile Pods 1 through 6 at the group heading for the Mass Relay. Cease forward burn, full reverse burn back us off!" Iago ordered.

"Yessir!" Weps and Helm replied. Almost immediately the deck started vibrating as the London's ten 25cm Mass Effect Field Augmented Helical Railgun Batteries opened fire at a rate of one hundred eighty rounds per minute, hurling 550-kilogram projectiles down range at 25,000 kilometers per second, with each shell hitting with forty-one megatons of TNT. The pitch of the engines changed going from forward propulsion to full reverse thrust, throwing the Heavy Frigate into reverse.

At the same time the flanks of the London was engulfed in fire, smoke, and hot exhaust gases as six Inferno Missile Pods engaged their electromagnetic rails and hurled their missiles into the void, forty missiles leaped from each pod already powered up, their micro-fusion drives engaging and propelling the missile and it's ten megaton antimatter enhanced Casaba Howitzer warhead towards their target. By UNSC standards it was a relatively small salvo, only two hundred forty missiles. The aliens on the other hand, judging by how their ships reacted were at the same time stunned and flabbergasted to see a ship launch so many hyper-velocity missiles in one go.

"Scratch two and three!" Weps said as Romeo-nine and ten, both frigates were hammered by dozens of rounds, their lightweight kinetic barriers having been quickly worn down by the hail of shells and then the light ablative ceramic armor offering barely any resistance to the hypervelocity tungsten shells. Romeo-nine lost her forward most thirty meters and Romeo-ten was torn in half by numerous shells. Their markers winking off the display and thus out of the fight.

The alien ships that were going after the Ellen Anders was beset upon by Inferno missiles. The alien point defenses however while potent they obviously hadn't been designed with such large numbers of missiles in mind, particularly the hyper velocity monsters that the United Nations Space Command Defense Forces used. Two hundred five missiles got through the point defense and detonated, blinding white spheres of ten-megaton thermonuclear destruction enveloped the alien formation, each blast lost fifteen percent of its power to vacuum, the remaining eighty-five percent of the warhead's power was directed into a lethal jet of plasma.

Kinetic barriers were overwhelmed in an instant, the ablative armor proved to be insufficient for keeping hypersonic jets of plasma out thus allowing the jets to tear the alien hulls asunder. As the blinding light cleared, the devastation that the Infernos had brought was incredible, one of the Frigates was completely gone, it's Eezero core have being bisected by a plasma jet. The other frigate has been snapped in half, the bow having been laid open effortlessly while the stern nowhere to be seen, the Eezero core having destabilized from the frigate's rapid unplanned disassembly. The destroyer analogue had actually weathered the storm the best, her hull had been torn open in over a dozen places and she had fires crackling within her hull not to mention she was bleeding air with her engine thrusters cold. But she was intact.

"That's three more kills! This is going to make one hell of a after-action report." Weps whooped absolutely giddy as Romeo eight, thirteen, and fourteen winked off the display.

"Guns, hurry up on pinning down those two flanking destroyer/frigate groups. We won't be able to outrun the hostile cruisers and battleship in reverse for much longer!" Iago said as he glanced at the display.

"Working on it sir. Hostile ships have extreme maneuverability and they are abusing the hell out of it. The computer is having a hard time predicting their movements. But we got them locked down, they try to fly straight in order to get some shots off our guns will tear them to shreds." Weps replied.

"Alright, keep at it. What's the charge status of the MAC?" Iago asked.

"About seventy-percent." Weps replied.

"Good enough! Target Romeo-Four! Helm, after we fire plot a random slipspace jump in accordance with the Cole Protocol." Iago ordered.

"Yessir!" Weps and Helm replied.

Romeo-Four like Romeo-Two was a Cruiser analogue that formed an intricate part of the clever trap that Iago had seen and he knew that eventually the enemy warships would encircle him and that it would also take a few minutes for the slipspace drive to charge, during that time the Omni-directional hardlight barrier would have to be taken off line. Plus reversing course and doing a full burn in the opposite direction was unlikely to work because these ships clearly used Element Zero and would have no problem running down the London. Which meant he had to smash his way out and make the enemy become a victim of their own momentum, using the chance that provided to escape.

Unfortunately that meant going right between two cruiser analogues and a battleship analogue. Given the beating they had delivered to the hardlight barrier earlier, if they timed it right then they would rather easily tear the London apart. "Fire!" Iago ordered.

The Hardlight barrier dropped for a fraction of a second as the MAC discharged. Hurling it's one hundred ton payload at a greatly reduced 9,180 kilometers per second. Romeo-Four seeing it's doom coming went evasive the moment it picked up the shell hurtling toward them. But even with the Element Zero core reducing the mass of the ship, with the range a mere 85,000 kilometers, they only had a mere nine seconds to react.

As it stood the Cruiser's evasive maneuvers saved the ship from getting gutted in fact it nearly saved the crew. The kinetic barriers flashed as they struggled to deflect the round, two titanic forces dueling violently. The Kinetic Barriers won and the round was deflected, the projectile going wind-milling end over end into the void. But it had almost completely arrested the ship's forward movement and judging by the way she was moving now, which was rather lazy with a lot of drift compared to her previous course. The Inertial Compensators had probably failed, which meant undoubtedly fatal results for the crew.

"That's a kill number seven! This is a cracking good day!" Weps said gleefully, thrilled that her gunnery crews were doing so well. As the computer came to the logical conclusion of what had happened to the crew and had the ship's marker wink out.

Regardless now was the London's chance to escape. "Reactors to three hundred percent, switch to forward thrust, engines all ahead flank!" Iago ordered.

The engine banks of the London exploded with light and the frigate rapidly arrested all of her reverse velocity and quickly accelerated forward. The two cruisers which had been using their superior speed to rapidly close on the London were suddenly victims of their own forward momentum, even as they wheeled around. The two remaining frigates and destroyers couldn't get any closer for the secondary batteries would tear them to pieces. The only thing between the London and freedom was Romeo-one, the hostile battleship analogue.

Suddenly the hostile battleship rolled and presented her broadside arc, which contained no less than sixty Frigate-grade mass accelerators. At a range of fifty-two thousand kilometers the ship opened fire. Fifteen kilogram ferrous slugs were accelerated to a velocity of ten thousand kilometers per second, meaning each slug was hitting with the force of 179.25-kilotons with a rate of fire of one shot every three seconds and at this range it was impossible to miss. The battleship salvoed her broadside guns, by the time the first salvo was two seconds away from impacting the London which was starting to roll in order to angle her armor, the second salvo was leaving the barrel and the recoil force from that had the guns chambering the next salvo.

The results were in a word, devastation. The London had sixty-five centimeters of Titanium-C3 Battleplate, an alloy of carbon nanotube reinforced Titanium-Tungsten alloy, with a Titanium-Tantalum alloy core. While in between the armor pieces was shock-hardening fluids, elastic polymers, ultra-high temperature ceramics, and capsulated healing agents that could seal minor hull breaches automatically, with as a final layer between the armor and the hull being a stuffed whipple shield. Sadly, this armor belt was good enough for only glancing hits and maybe a couple of frigate grade mass-accelerator not sixty rounds slamming into the ship all at once.

Titanium-C3 Battleplate rent and screamed in protest as it was horrifically clobbered by sixty 179.25-kiloton impacts. In several areas the shells punched through the armor and plowed deep into the ship. The London rolled violently from the impacts. The second and third salvo of rounds devastated the frigate, Titanium-C3 fractured and spun through the void, the light of the local star catching the pieces and glinting in the sunlight. Pretty in appearance but tainted as rounds tore through the armor and got at the compartments beyond.

The follow up salvoes from the Battleship's main guns proved to be the London's undoing. Eight rounds, each weighing seventy-kilograms going at 25,000 kilometers per second slammed into the Frigate with just over 5-megatons of destructive force apiece. The force of the blows nearly snapped the old Paris class Heavy Frigate clean in two and neatly severed her main thrusters from the hull. The London's running lights flickered dimly for several minutes before going out entirely.

The two alien Cruisers having overcome their own forward momentum came up to the dead and drifting London. One of the Cruisers deployed multiple shuttles to board the ship while the other Cruiser moved to an overwatch position. Meanwhile the two surviving destroyers and frigates moved into an escort position next to the Battleship.

The bridge of the London was an utter disaster area. Broken pipes and conduits dangled from the ceiling, sparking erratically. The normal lighting had gone out and the red emergency lighting had come on in its place, most importantly the rumble from the reactor was gone. "Damage report!" Iago barked.

"Believe me sir, you don't want to know. It would be easier to tell you what isn't damaged." The engineering officer said.

"Alright, give me the quick version." Iago said.

"All three reactors are offline were down to emergency power, maser communications dish destroyed, tight-beam laser communications system destroyed, QEC destroyed, slipspace drive destroyed, back up life support destroyed, MAC system destroyed, all of the Inferno pods are either destroyed or offline, CIWS and Point-Defense either destroyed or offline, Harpoon torpedo silos are damaged we can't launch them. Even if the thrusters were still attached, the hull is so badly damaged we won't be able to go anywhere." the engineering officer replied.

Damnit, with the reactor offline that means the self-destruct is offline as well. But the Cole Protocol is clear, the capture of a ship board AI is absolutely unacceptable. Iago thought sourly. Then a bolt of realization struck him, the reactor may have been offline but they still had plenty of nukes.

"Sir, hostiles are moving to board. We have suffered severe casualties to both Marine and crew compliments. Our chances of successfully repeling a boarding action is approximately twenty-five thousand to one." Igla said stiffly.

"Noted. Weps, arm our entire load of Perseus class nukes and transfer detonation command to my station." Iago ordered, referring to the thirty-megaton thermonuclear devices that were the first layer of defense against plasma torpedoes, when detonated the electromagnetic pulse would destabilize the magnetic bottle that the plasma was contained in enough that it would render the plasma torpedo inert. Just one of these things had enough power to turn the London into a pinata when she was intact, setting twenty of the damned things off simultaneously in the shape that the London was in would simply vaporize the ship. The Cole Protocol was absolutely clear, the capture of a UNSC Warship or it's onboard AI was absolutely unacceptable and in this case the London wouldn't be able to flee which left blowing themselves up as the only option.

"Yessir." Weps said before typing in the commands and then looking up. "It's done."

"Good, Igla any sign that our friends have detected us arming our nukes?" Iago asked and Igla shook his head in response.

"Anything onboard this ship and within one kilometer of this wreck is going to get seriously fucked up when we blow the bombs." Iago muttered before speaking up. "Gentlemen, it's been an honor and a pleasure to serve alongside you. First round is on me." he said and then hit the "detonate" command and the world turned white.

The UNSC London ceased existing in a brief white flash as a 600-megaton thermonuclear blast was birthed into existence. What little survived the detonation was flung outwards at incredible velocities, the shrapnel followed closely by a wave of radiation. The kinetic barriers of the cruiser had been knocked offline by the point blank Electromagnetic Pulse was riddled with dozens of pieces of Titanium-C3, Vanadium Steel, and TR Alloy ranging in size from peas all the way to Pelican Dropship with some fragments being even bigger. The armor stopped most of the pieces, but the two largest pieces tore through the armor like paper, then the radiation burst hit. In an instant just over a quarter of the ship was flooded with lethal levels of radiation.

Onboard the Turian Flagship Redemption

15th Citadel Patrol Fleet

General Vocus Tanirian Commanding

"Well that could've gone better." Vocus Tanirian, recently promoted to General hissed as the remains of a nuclear fireball dispersed in the form of black dust where the enemy Cruiser had been. One Cruiser, one Destroyer, and three frigates destroyed, with another frigate and Cruiser mission-killed, another Cruiser heavy irradiated by the nuclear radiation released by the blast, and his remaining destroyers and frigates having suffered minor and moderate damage respectively.

"Agreed that could've gone better. I think what we have just learned is that even if they only use a little Mass Effect, that doesn't mean they are inferior to us. Hell, according to scans, that thing's main gun used only electromagnetic coils to propel a slug of a size that Destiny Accession would be jealous of to a velocity that is roughly half of the velocity of our main guns, but because of it's great mass, about 100-tons when that round hit nothing short of the kinetic barriers on the Redemption would be able to stop it." The captain of the battleship Redemption, Juius Ramlin said.

"That said, I think what we encountered was their largest combat class. However if it wasn't, then I shudder at what they would consider a Dreadnought. We are most certainly going to need more forces to bring these newcomers which honestly have no idea about the dangers of space into the Turian Hierarchy." Vocus said, still shaken at the brutal kicking that one ship had given his fleet.

"I recommend that we find out how many relays have been activated and that we get a Pacification Fleet out here, show these upstarts not to mess with the Hierarchy." Juius said.

"Don't be so sure, just one ship damn near gutted my patrol fleet. So don't be so quick judge, a well coordinated force using those ships will cut just about anything to pieces in short order." Vocus said.

"True, still what do we do now?" Juius asked.

"Launch probes, they are to head through the activated Mass Relay and figure out how many other relays have been activated. After they return, we are to the nearest fleet base and report our findings. Hopefully we can get an expeditionary fleet out here and bring them into the Turian Hierarchy." Vocus replied.

"Given the fight we just went through, I doubt that they will go quietly. If anything, they'll probably greet the expeditionary fleet with magnetically accelerated slugs and swarms of missiles. Our point-defenses are potent but the biggest problem they have is their relatively short range, our newest GUARDIAN Lasers only have a range of three thousand kilometers and that's maximum range, they get effective at just over a thousand kilometers, those hyper-velocity monsters that they use can cross that distance in a matter of moments then of course there is that warhead what the hell was it?" Julius asked.

"That's the thing, judging by what the scans say, they were nuclear warheads but the damage doesn't fit. If anything, according to DAMCON it appears that they were hit with a gigantic HEAT warhead." Vocus said.

"Spirits, you mean that warhead was a nuclear HEAT charge?" Julius asked stunned.

"It's the only viable answer considering the damage. They tore down the kinetic barriers pretty quick too, they just aren't designed to stop plasma jets the same goes for our armor." Vocus said briskly.

"Yeah, exactly. Regardless I wonder how this is going to go over with the Council? They will most certainly notice a Expeditionary Fleet moving." Julius said bluntly in a statement of fact.

"We don't have to tell them. We just have to alert fleet command that we encountered someone activating a dormant mass relay in violation of Citadel Law and they'll dispatch a fleet." Vocus said, but judging by way his mandibles flared he knew that these upstarts wouldn't go down easily.