Prologue: Infection

Disclaimer: I don't own Mass Effect or Dead Space in any way.

Author's note: The story takes place after paragon Shepard and the entire team had destroyed the Collector Base. Isaac is still on the Ishimura before he leaves it for Aegis VII to return the red marker before it enters the Mass Effect universe.

Edited by my sister.

In the center of the Serpent Nebula was the Citadel, the massive space station that was home to the powerful Citadel Counsel who maintained the balance with all united alien civilizations; it was just a normal day for the millions of people who lived on the grand space station, along with the hundreds of space ships that traveled to it daily. On the space station was Citadel Control, the main hub for organizing ship docking and making sure scans of the nebula were clear of hostiles. All the technicians in the control room were busy working on their computers, Omni-tools, or talking to different ships through the com-system. Many of them were tired out from the constant work, or just plain bored with their job. One extremely bored turian stood out, since he was the only one not busy talking to any of the approaching ships and was just slowing working on a small report.

"In coming system scan report." Spoke a cool female voice of the Citadel Control command computer VI.

Giving a bored sigh, the turian technician saved his report and started typing on the console, making the recent scans taken around Citadel Space appear on the screen. He was pretty sure there was nothing new or important about the scans, but ever since the attack of the Geth and Sovereign, it had become a full daily routine. However something new had appeared on the report and it was big. With a concerned look, the turian closely read the report to make sure what he was read was correct. Quickly, he turned his seat around to look at a human, who was the staff supervisor, standing in the center of the control room and looking over the shoulders of the other technicians' work.

"Sir, we have an unknown spacecraft entering the Nebula and heading towards the Citadel!"

"What is it, the Geth? How could they have traveled here through the Mass Relay without being caught?" The staff supervisor demanded as he hurried over to the turian's computer to look at the report.

"That's the thing sir…it just appeared out of nowhere. It must have been traveling with engine power alone or maybe a FTL System, but it would take months just to get here from the nearest star system."

The supervisor shook his head as he read the scan report, then looked through the control room window and out at the glowing Nebula. Far off in the distance was the ship, which seemed like it was just cruising out purple light of the star.

"Get one of the station's cameras to zoom in on the approaching ship." Commanded the Supervisor with his tone dark and serious as he gave the orders to the turian.

The turian nodded and typed in a new command, making the screen change into a closer view toward the distant ship. The supervisor leaned in closer a pressed a key to zoom the camera closer until they had a full view of the ship.

"My god…It's huge…" Muttered the turian as the ship slowly continued to drift closer towards the Citadel.

"It looks like mining ship of some kind and it seems like it is in bad shape. Multiple hull breaches, engines on backup and gravity systems seem to be disabled in many parts of the ship." Commented the Supervisor as he made the camera pan around to view all the angles of the Citadel, stopping it when came over the name of the ship.

"The USG Ishimura…Sounds like a human ship, but it does not look like any of the ships they have." Commented the technician as he started to do a scan of the vessel.

The staff supervisor nodded and then answered back. "You're right, maybe this is one got lost and the crew either evacuated or died out."

"Well…For a ghost ship there seems to a lot of movement inside, even a few life signs from what the scanners say." The turian said with a nervous look in his eyes.

With a blank look, the supervisor moved back to the center of the control room and yelled out; "Everyone, we have a large damaged ship coming in towards the Citadel with possible injured personal inside! I need all ships to either dock right now or back away from the Citadel for an emergency docking; we got a least thirty minutes before it reaches us, so get moving people!"

Citadel Control was in a rush of action as calls to ships were made and rapid commands were typed into multiple computers, making ships quickly dock or quickly fly out of the Citadel. As the USG Ishimura continued it's slow drift towards the space station, the staff supervisor called C-Sec office to get some officers and a medical team ready for whoever or whatever may be on the ship.

Inside the main docking bay, the C-Sec and medical team stood by the airlock doors until there was a beep and a light on top of the door glowed green, followed by the doors opening with the hiss of decompression.

"Alright everyone, our job is to see how bad the situation on the ship is. From what we know, the power is out in many parts of the ship, but since the ship is docked we don't have to worry about life-support." said the leading turian C-sec officer to the other members of the team.

"Be ready for anything, for all we know this ship may have husks or even Geth on it for all we know." He pulled out his M-3 Predator and checked to make sure the thermal clip was in place with a small sinister chuckle at the idea of a good fight.

Some of the other officers laughed a bit as well and took out their own weapons, but the medical team just shook their heads with disapproval. The leading officer then walked into the air lock and pressed a button to open the second airlock door into the Ishimura. The leading officer gave a curse as he looked into the pitch black darkness of the ship. Suddenly, yellow glowing eyes appeared in the darkness to stare out at the two teams ominously.

"What the hell…?" Muttered the leading officer as more glowing eyes appeared in the darkness, followed by low growls toward them.

Raising his gun up he flicked on the flash light and then gave a terrified scream at what he saw, before a sharp bone blade stabbed right through his throat. He dropped his gun as his hands grasped at his neck to try and stop the bleeding until another blade cut through his armor shields and sunk into his chest. Falling to the ground, he could hear the bloodcurdling screeches of the deadly creatures rushed pass him, followed by the rest of the team firing their guns franticly until screaming into horror and pain before his vision faded into darkness…

Author's Note: Anyway, this was my first shot at writing a cross-over. Please R&R my story to give me any corrections or complaints about it. First chapter will be out soon, thank you for reading!