When Isaac opened his eyes, the room was dark. Someone had dimmed the lights. He rubbed at his eyes, wondering how long he had been asleep.

"Ellie?" he called. There was no answer. He lifted his head, looking around the room. "Ellie?" She wasn't there.

Isaac stood up, shaking his head. He walked to the door, and it opened as he approached. He stood there, staring around at his unfamiliar surroundings.

Opening up his RIG communications network, he said, "Ellie? You there?"

"Oh, Isaac, you're up."

"Yeah, I am. How long was I out?"

"A few hours. I turned the lights out for you."

"Yeah, thanks. Where are you?"

"Down one deck. Engineering. Isaac, this ship is amazing! I've never seen anything like it. It's smaller, faster, and a lot more powerful than anything in EarthGov's fleet. You've got to come see!"

"They just let you wander around the ship?"

"Well, the commander seems to trust us. He's allowed us access to most of the ship. Now, come down here and see this engine! I guarantee you won't regret it."

Isaac sighed, and a passing crew member shot him a glance. "Fine, I'll go look at the engine."

"Great. Just take the elevator down one floor, and it's the first door on your left."

Isaac approached the elevator, the door opening as he neared. At least the doors seemed to work the same way in this universe, it seemed. A small, holographic menu blinked to life in front of him, and he selected the option for deck four. The doors slid shut, and the elevator hummed softly for a few seconds, before the doors reopened. Isaac stepped out into a small hallway. On either side of the elevator was a door, so he entered the one on the left. Beyond it was another door and a staircase leading down. Going through the door, he found himself in a room filled with conversation and the hum of the ship's engine.

"Isaac, over here," Ellie called. She stood near a console, talking with Tali. As Isaac approached, she grinned at him. "This ship is incredible."

"It does seem pretty nice," he agreed.

"And you haven't even seen the drive core yet. It uses something they call Element Zero. Isaac, they've mastered faster-than-light travel without the use of ShockPoint Drive that they can use on any size ship! It took decades just to be able to get ShockPoint to work on a ship the size of the Ishimura. This is so much more advanced than out universe."

Our universe. Isaac still wasn't used to hearing that yet. "Yeah, it's really amazing."

"This ship is the most advanced vessel in the galaxy," Tali commented. "If you only go by this, you might overestimate the rest of our technology."

"Well, you may be right," Ellie said, "but where we're from, it's almost impossible to achieve faster-than-light travel on anything larger than a personal transport." She sighed. "Here, you can move gigantic ships across the entire galaxy in a matter of seconds."

Isaac turned to Tali. "How do you manage to do it here?"

"The only way we can accomplish it is by using Element Zero. It's a rare material with incredible properties." Tali turned and led them down a short catwalk, at the end of which, the drive core sat glowing. "When an electrical current is run through it, it can change the mass of the space-time field around it. A positive current increases the mass, while a negative current decreases it. Basically, it allows us to negate the mass of the ship enough to reach faster-than-light speeds."

"That sure is handy," said Isaac. "Is there anything else it can do?"

"Any number of things. We can use it to create shields and barriers. It powers the projectiles of our weapons, and the field it generates can even be used as a weapon itself."

"One element can do all that?" Ellie said, amazed. "Now I can imagine how your technology has advanced so much further than ours." She turned to gaze at the drive core.

"Engineer Clarke," came EDI's voice seemingly out of nowhere.

Isaac looked around, bewildered for a moment, before remembering the AI. "Oh, uh... Yes?"

"There is a situation in the cargo bay. I believe your presence there would be beneficial."

"A situation? What kind of situation? And why should I be there?"

"My sensors have detected a burst of plasma energy discharged in the bay. I believe it came from one of the devices on board your ship."

"Oh. Yeah, I guess I should check it out." He turned back to Tali. "Uh..."

"Deck five."

"Thanks."

Isaac jogged to the elevator then headed to the bottom deck. As the doors opened, the sound of a heated argument reached his ears.

"Look what you've done, Vega! You blew a hole in the side of my shuttle!"

"How was I supposed to know it was loaded?"

"That's my point! You shouldn't be touching it at all. Now I'm gonna have to repair this damage. God, this will take days."

"Lighten up, Esteban. I thought you liked fixing that thing up."

"There's a difference between fixing it up and actually fixing it. Now put that thing down before you do any more damage."

Two men stood in the center of the cargo bay, arguing with each other. The larger man held Isaac's plasma cutter and waved it around wildly as he spoke, while the other attempted to remove the device from the first's hands.

"What are you doing with that?" Isaac asked, loud enough to make sure they could hear him.

Both men turned, and the one holding the weapon shrugged casually. "Oh, sorry. Is this yours?"

Isaac frowned and looked over at the shuttle. A smoking scorch mark showed where the weapon had 'hit. "Yes, that's mine. What are you doing with it?"

"Hey, calm down, man. I was just looking at it."

Isaac shot a look at the hole in the shuttle. "You could have killed someone with that. Hand it over before you damage something else."

The man sighed. "Fine. Here, take it." He tossed the weapon to Isaac, who barely managed to grab it before it hit the ground. "You guys are too uptight." With that, the man sauntered away to his own little corner of the cargo bay, and began busying himself with something on his workbench.

Isaac pinched the bridge of his nose as he clipped the plasma cutter on to his belt, then turned to the other man, who was frowning mournfully at the shuttle.

"Hey, sorry about that," Isaac offered as an apology. "I should have made sure the weapons were secured in the ship."

"It's no problem," The man replied. "He probably would have found it anyway. It'll be a pain, but give me a few hours, and this bird'll be ready to fly again." The man turned to Isaac and held out his hand. "Steve Cortez. Normandy shuttle pilot and requisitions officer."

Isaac shook Cortez's outstretched hand. "Isaac Clarke. CEC engineer."

"Nice to meet you, Mr. Clarke."

Isaac groaned. "Ugh, don't call me Mr. Clarke. It makes me feel like an old man. Just call me Isaac."

Cortez smiled. "And you can call me Steve. The muscle-bound blockhead over there is Lieutenant James Vega."

"I can hear you, Esteban," James called back.

"That's why I said it," Steve countered. He turned back to the shuttle, shaking his head. "Honestly, I'm surprised that there's this much damage to the shuttle. I know the barriers were down, but still… That must be one hell of a weapon."

Isaac glanced down at the plasma cutter on his belt. "It's not even a weapon, really. It used to be a tissue laser, for surgery. But…" Images of the necromorphs crawling around Titan Station flashed in his mind. "The situation called for a different use."

Steve looked at Isaac, frowning, but decided to leave the subject alone. "A plasma cutter? That sounds more like geth technology. Most of our weapons use mass fields to fire."

"Tali mentioned something about that earlier. How does that work?"

"Well, I'm probably not the best person to ask about that. If you want to know about weapons, you should talk to Garrus. If you want, I'll have him take a look at your weapons. He might be able to modify them to work with thermal clips."

Isaac rubbed the back of his head. "I don't know if that would be worth the effort. I've had experience fighting, but I'm no soldier."

Steve shrugged. "It wouldn't hurt to have him take a look at them anyway. If we had weapons like this on the front lines…" He looked back at the shuttle. "It might make a huge difference."

"Against the Reapers," Isaac mused.

"So you've heard about them?"

Isaac shook his head. "Only what they're called. I don't know anything else about them."

"They're a race of sentient machines, bent on exterminating all life in the galaxy," Steve explained. "They… They killed my husband." His expression became pained. "I was there when they took him. I could have helped him, but he wanted to make sure I got away safely. He sacrificed himself for me." His voice faltered. "I'm sorry, I just-"

"I understand," Isaac said, putting a hand on Cortez's shoulder. "I had a girlfriend, Nicole, working on a starship, the Ishimura. There was a problem, and the ship went dark. They sent in a repair crew to see what happened. I was part of that crew. When we found the Ishimura, we found out that the entire crew had been slaughtered and turned into these creatures called necromorphs. I had to fight my way through them to survive, while the rest of my crew died. For all I know, one of the necromorphs I killed was Nicole. She was never found."

The two men stood there in uncomfortable silence, sharing each other's pain, until a voice broke through their silence.

"Engineer Clarke," said a voice, not EDI this time, "Commander Shepard would like to see you in the War Room on Deck 2."

"Well then, I guess I'd better go," said Isaac. He held out a hand to Cortez. "It was nice to meet you, Steve."

Cortez grasped his hand, giving it a firm shake. "And you as well, Isaac. See you around."

"See you, brujo," James called from his corner.

Isaac looked back at him, rolling his eyes, then proceeded into the elevator. When the doors opened, he found himself looking at a large, spinning hologram of the galaxy. A woman standing next to it at a console looked up and smiled at him.

"Ah, you must be Engineer Clarke," she said.

"Just Isaac is fine. Are you the one who called me up here?"

The woman smiled again. "Yes, that was me. I'm Specialist Traynor. I monitor all the signals going in and out of the ship. Commander Shepard is waiting for you in the War Room." She pointed to a door to Isaac's right. "Just through that door, past the scanner and down the hall."

"Right, thanks." Isaac went through the door and passed through the scanner. The two crewmembers guarding the door didn't even seem to notice him as he went through. He passed by a small conference room of some sort, then turned the corner to find Commander Shepard waiting for him.

"There you are. Follow me."

"Just one thing after another, today," Isaac muttered, but he followed anyway.

Shepard led him through a circular room filled with consoles, and a large hologram of some sort of device.

"What's that?" Isaac asked, pointing at the hologram.

Shepard glanced at him, then at the model. "We've been calling it the Crucible. It's a Prothean device that we believe is capable of defeating the Reapers."

Isaac stopped, folding his arms. "And just what are the Reapers? I don't really know much about them, aside from the fact that they're machines that want to destroy everything in the galaxy. If I'm going to be living in this universe, I'd like to know what's trying to kill me this time."

Shepard turned to Isaac, then hit a button on the console. The image of the Crucible was replaced with a model of a large, insect-like machine. It had a long, curving carapace of a purple metal. Five large legs supported it at the bottom, and another six, smaller legs were curled up underneath it. "That," the Commander said, "Is a Reaper." He tapped the console again, and another image appeared. This one was smaller, with stouter legs. The images began to cycle through images of ships and distorted creatures.

"The Reapers are a race of sentient machines that have been around for millennia. Every 50,000 years, they emerge from the dark space outside the galaxy to eliminate all organic life. They harvest the civilizations of the galaxy to create new Reapers. Those that aren't harvested are turned into husks." The image changed to a distorted human figure with glowing tubes wrapping around its body. "Husks are dead organic life-forms, bonded with synthetic technology to obey the Reapers." Shepard leaned against the console as the image changed back to the Crucible. "We've been fighting the Reapers all across the galaxy. We've been managing to hold them back as best we can, but they're starting to overtake our forces." He sighed. "Right now, our only hope is to be able to build the Crucible and use it against the Reapers." He stood back from the console and fixed his gaze on Isaac. "We've got to use every advantage we can get in this war. Now come on, Admiral Hackett wants to see you."

Isaac followed the Commander into a small side room where a large, glowing platform took up half of the room. Shepard walked over to a console and activated it. The platform flickered and lit up with the image of a scarred man in a military uniform. The man stood at attention and saluted. "Commander," he said.

Shepard returned the salute. "Admiral Hackett."

The admiral took a more relaxed stance and put his hands behind his back, looking over at Isaac. "So, this must be Isaac Clarke."

Isaac sighed. "Is there anyone here who doesn't know about me?"

"You're from another universe, son. That's bound to attract attention. We've studied the schematics for your telekinesis module, and it's already given us a huge advantage in the field. Our biotic soldiers are several times more powerful than they were before, thanks to that technology." He turned to Shepard. "However, there is also the matter of the artifact you picked up, Commander. Our scientists have been studying it, but we can't seem to figure out anything about it. It doesn't seem to be Reaper or Prothean in design. We can't make heads or tails of it."

Isaac shook his head. "I'm sorry, but what is this artifact, and why does this have anything to do with me?"

"I was thinking that this artifact may have come into our universe when you did, somehow. Perhaps whatever brought you here brought it as well."

For some reason, this sent a shiver down Isaac's spine. "This… Artifact. What does it look like?"

Hackett paused for a moment, as if thinking. "It was a large chunk of stone. Deep black, and covered with symbols that none of our translators could comprehend. Why, does it sound familiar to you?"

Isaac put a hand to his forehead, where he could already feel sweat forming. He stumbled back until he hit the wall behind him and slid down it until he reached the floor.

"Isaac?" Shepard asked. "What's wrong?"

"The… The Marker… It followed me."