The Normandy was a fascinating ship – insofar as the stealth systems were concerned. The people here had only just cracked emissions-based stealth systems, it appeared, and that was only thanks to the shortcuts provided by Mass Effect technology. In the early days, developing their infamous Prowlers, ONI had issues figuring out how to move the damn things while they were in stealth mode, since even low-end emissions were like a flare in the vacuum of space.

ONI had gotten around that thanks to induced geometric distortions around the engines that made the emissions appear consistent with surrounding background radiation levels. Normandy, however, used a specially-designed Mass Effect core that – when its operating mode was switched to stealth mode - generated micro-singularities in front of the ship that the Normandy was pulled into. Anything that could detect anomalous gravitational readings (say, for instance, sensor packages that were specifically designed to measure space-time curvatures for smooth entry into an alternate subdomain of existence) would be able to detect the vessel, but for spacecraft measuring the easy things – heat and radiation – Normandy would be invisible. That meant – as far as modern galactic society was concerned – the Normandy was a one-of-a-kind stealth ship.

(The technology gave her an idea to throw into the Halcyon being built – which she tied up in a nice, neat, digital bow, and sent it off to her sister instance.)

That, according to the Commander at least, was why Normandy had been sent into the Traverse in order to track down Saren. Cortana wasn't the only one being given a look at the Alliance frigate – the others were as well, along with a short crash-course on what the ship was, and the theory behind it.

The designs for the Normandy drive core were classified, as were the heat sinks and everything else that allowed the stealth systems to run. But, the underlying theory behind them had been around for centuries by now, it was just a matter of the technology developing to the point of making it possible.

Cortana's splinter couldn't lie to herself – literally or figuratively at this point – she questioned the wisdom of sending only one ship in after a rogue agent with an army at his beck and call.

The guided tour ended down in the cargo bay, which is where she saw fit to voice those thoughts.

"They're sending one ship in after an army?" Cortana scrunched her nose. "That doesn't fill me with confidence."

"Well, maybe your geth partners could help," Tali retorted, almost accusatory.

"They… would be a big help," Garrus agreed, causing the Quarian to shoot him a dirty look before clearing his throat.

"Confidence or not, we've got a job to do," Shepard clasped her hands behind her back. "And it's up to us to do it, no matter the cost. We've got about…" She checked the clock on her omni-tool. "Eighteen hours to Therum, depending on relay traffic. Once we're out that way, I want everybody suited up and ready to go. Until then, get settled in somewhere comfortable, but not in the way. Dismissed." She turned, and walked into the lift, taking it up to the next level while the others were left to fend for themselves.

Cortana frowned, staring at the lift before movement out of her periphery caught her attention. "That's it? Bark orders and vanish? I know Commanders kind of do that, but we're new crew!"

"Don't take it personally," Alenko shrugged. "She doesn't socialize with the crew."

Cortana turned, raising an eyebrow. "She socialized plenty back on the Citadel."

"You weren't crew then – you are now." Alenko answered.

"Man, that's the most bass-ackwards shit…"

"Tell me about it," Williams agreed. "When she first got up in the medbay it was 'pleasant to see you, Williams – are you doing okay? Need anything?' The moment Anderson said I'd be staying aboard the Normandy for the foreseeable future, it was like she clamped down."

Cortana's splinter tilted her head up, and cast her mind back in thought. Doctor Halsey had tried the same with the Spartan-IIs – even though they were in her care, Halsey had tried to keep them at arms' length, at first. It failed, because they were children, and Halsey had an undiscovered mothering instinct that was far too strong to be overcome.

She could see something similar here, though. As a soldier, no posting was ever truly permanent. And then, there was always the risk of combat. Back home, there were more than a few people – survivors of glassed planets and other Covenant attacks – that dared not get too close for fear of a repeat. The Spartans especially (just because they didn't tend to socialize outside their brothers and sisters in MJOLNIR Armor, didn't mean it didn't happen) usually kept away from normal, unaugmented humans. Even other soldiers.

Regular people died too easily.

It made sense, looking at Shepard's record. Born to parents that were total strangers (quite possibly not even knowing her own birth name), moving around as a child in the slums of Earth, then Elysium occurred where some people were no doubt dragged away by slavers, Akuze where her entire squad was wiped out, and Torfan – where her decision to press the attack got them killed.

"That's a shame," The AI commented out loud. "Unit cohesion's better when everybody's on good terms."

"Or when everybody can think at lightspeed," Tali muttered under her breath, before finally deciding to fuck off to the engine room. Lucky her – Cortana's splinter wanted a look at that core.

"You don't need to worry about that, ma'am." Alenko turned to her directly. "The Commander may not care to socialize, but she'll have your back."

The AI detected an unspoken hint of complete confidence there in his voice – a thread she just had to pull. "You've known her for a while?"

The man thinned his lips for a moment. "We both served under Captain Anderson before we were posted here. But she didn't care to socialize before. I've seen her in combat, though – she doesn't stop trying."

"Hmm…" Cortana hummed, before clapping her hands. "Well, unlike some people, I like to get to know the people I'm going to be working with." She glanced at the others. "Anyone have some interesting facts about themselves? Deep, dark, embarrassing secrets? I promise, I won't record them for later."

Just to tease them a bit, she clicked on a red light – a blinking diode hidden in an optic that was a vestige from the original geth platform design - to indicate a hardware failure in case the programs couldn't communicate it for whatever reason.

No one seemed to be stepping up, which caused Wrex to chuckle.

"What's the matter?" The Krogan rumbled. "Don't wanna be famous on the extranet?"

Kaiden looked scared for a moment… before he finally seemed to realize Cortana was joking, and he sighed.

The honeycomb internal framework – the very most basic skeleton around which the rest of the ship, the other maintenance corridors, main corridors, and everything else – was completed first. It gave the impression of an Autumn-class, built out of those construction kits for children. Everybody knows the ones – the little plastic rods and sheets that snapped together thanks to plastic adapters.

With the initial wireframe done, now the actual work could begin on the rest of the ship. Ordinarily, UNSC ships were constructed from the innermost core, outward. That is, to say, from the launch bays (which on most cruisers were on the ship's middlemost level), to the rest of it. That way, while the vessel was under construction, the larger vessels (like cruisers) could more easily receive shipments of supplies and materiel needed for the construction process, which is how you get things like 'Class-seven service corridors' that stick around even once the ship is completed – for easier intra-ship transport of heavy cargo.

While the drones set about doing that, Cortana's instance began contemplating the best way to gather up enough Element Zero for the new ship's retrofitted mass effect core. It could launch without it of course, but Cortana's instance would rather the ship set sail as 'feature complete.' But, the prioritizing was everything else.

No sense in delaying construction for a system that hadn't been part of the design in the first place. If only she – the original Cortana – had saved those ships they disabled, they could've been cannibalized for Eezo. Well, the past couldn't be changed.

The logical instance watched as construction proceeded on the ship, outward from the inside, before a ping through the geth network caught her attention. She opened the file… and was stunned at the audacity of it.

IES stealth on an Autumn-class? Like refitting the internal structure to house heat sinks rated to hold fusion engine emissions would be easy now that she had everything planned out and prepared.

Although… the utility of such a thing was too useful to completely disregard…

No, ONI baffler systems couldn't eliminate all engine emissions – and on a ship as large as an Autumn-class, with so many engines (especially ones that had been replaced with such more powerful models), the emissions would be far too strong for the systems to effectively mask. An Eezo core strong enough to generate singularities in front of the ship at a distance that didn't rip the vessel apart would need to be twice as large as the space she had for it. Plus, there was the need to hide the ship from the visible spectrum, since, you know, a 1.5-kilometer giant gun with engines tended to stick out.

But, updated baffler components thanks to having been in the mother of all Forerunner ships was on the table, and active camouflage technology could cut out the visual risk of identification without needing to sacrifice armor plating, like photoreactive panels would…

Sh-She'd save the idea for later. There'd be room for refits and revisions down the line, surely.

Adjusting to fill Avina's niche aboard the Citadel was not hard – a simple matter of pulling the VI's core information patterns apart, and assimilating the data into her own functions. The program did have some rudimentary security systems – damn good ones, actually, which considering it was spread out through the Citadel, made sense – but, in the end, the VI was just that. A VI. It thought at only the percentage of a speed Cortana could (even the splinters, which usually suffered a minute decrease in processing capability, still thought far faster), and couldn't adapt or react to threats.

Now, exactly how Cortana's splinter had managed to supplant Avina with her own self was quite clever on her part. Before leaving, Cortana Prime had the good sense to remain hidden inside her geth frigate, allowing her new copy to do her work, laying the groundwork for what she needed to do as well.

Avina's terminals didn't send back files to the main data center, only the requests that organics made of it, which meant just uploading into a terminal and following the link back was useless. After watching Avina help a tourist, however, she managed to slip one of her processes into the terminal through the connection Avina used to connect to omni-tools and provide navigational assistance. Identifying what exactly was generated when an organic spoke to Avina, Cortana's instance had slipped a few processes into other terminals when their connections opened to assist local tourists. Then, the processes would duplicate the latest help request, and send them back to Avina, ad nauseum, until the system crashed.

The idea was that – as the organics working on Avina to keep it working solved the problem – she'd exploit the connection for her own gain. As the number of faulty requests Avina received was so much, it'd force Avina to work through them. Simply deactivating the terminals that sent them would do nothing, as the requests would remain in the system, eating up processing power. The only thing the IT personnel staffing Avina's data center could do was clear the requests by resetting the system.

Which they did. From there, it was a simple matter of waiting nearby, while the main server restarted. When the techs contacted C-Sec's network division for assistance determining if the issue was a glitch or a deliberate attack, Cortana slipped her processes back through the line, and extended herself into Avina's data center. Thus, when she gave them the all-clear and they connected to Avina's core to wirelessly install a hastily-coded patch before restarting the system again, the UNSC AI made her move.

Entirely unbeknownst to the organics, the moment the connection was established, she had used that information to open a link of her own, and while the patch was being uploaded and installed, she subtly rewrote it to provide a backdoor for her. Then, when Avina restarted, it would be one of the first things to execute.

Faster than organic minds could perceive, let alone react to, the program she installed allowed Avina's wireless hardware to tap into geth channels, creating a high-bandwidth link between the data center and the geth ship. Cortana's duplicate had transferred herself through, and while the system was still booting up, tore Avina's processes asunder and assumed their functions. In order to keep suspicion off her, in the event that they went poking around in her processes, Cortana's copy created a little virtual machine to mimic Avina, and sent everything the IT personnel tried to do there.

When the reboot completed, and Avina's terminals began projecting the hologram of the skinsuit-wearing Asari, there was nothing to suggest that the VI had been replaced by an intelligence of far greater ability and repute.

If she was the gloating type (and she was, but she also had restrained), the latest iteration of Cortana would've transmitted something like "This intelligence has been purged; its matrix commandeered." But that'd blow her cover extremely quickly.

And in any event, she couldn't afford to. She had to compress herself quite a bit to slip into Avina's hardware, but that didn't mean the expansion of her neural pathways were halted. She had time. Not an excess of it… but enough.

One of Avina's – now Cortana's – terminals registered a Keeper walk by. Even the systems she was on could see the vast spectrum of energy connecting the alien to its brethren, and she reached out to it.

The Keeper slowed down from its approach to wherever it was heading.

"Hello? Hello, can you hear me?"

The insectoid alien did not respond. Their communication protocol was extremely unfamiliar – and highly encrypted. In contrast to the other organics, it looks like whoever engineered the Keepers actually put effort into obfuscating the Keepers' network.

But the protocol was there. It could be understood, deciphered. Instead of trying to convert it into a format she could understand, though, she did her best to put it in a way the Keepers could interpret, modulating the signal to mimic the signals coming from the Keeper's cybernetics.

"I want to communicate with you."

The Keeper continued to outright ignore her, but there was a burst of activity that came out of its pack in response. It was a bad idea to ignore her – no system stood against her for long. That activity gave her an idea, though.

Recording the short burst, Cortana's duplicate took the signal, and turned to another terminal across the station. Recreating the signal, Cortana sent it out at the nearest Keeper she could find.

"You! Big and green! I'm talking to you!"

The Keeper locked up… and slowly turned around. Seemingly curious, the insectoid creature walked over to the terminal, and began responding with data bursts.

Oh, curious – so the Keepers only responded to other Keepers. There must have been something in their signals, that could be recreated by sampling the signal and sending it out, but not emulated by just trying to mimic them.

The organic automaton began to click… and walked off. Then, however, something very peculiar happened. She could detect a shift in the signals coming from a nearby Keeper terminal, and the alien responded, going right for the thing like nothing else mattered. Once more, at speeds faster than any organic lifeform could perceive, the terminal's signals began to shift, as the Keeper responded with its own. Curious, she watched as the connection went on… before she finally felt like she'd gotten what she needed.

For the third time, Cortana turned to a different terminal, only this time, she began to project the signals out of it to a Keeper passing by.

"HEY! LISTEN!"

The passing alien diverted course, and walked right up to the terminal, like nothing was wrong. It began to communicate, and positively giddy, Cortana responded by mimicking the connection.

"Come on, connect to me you little shit…"

Then, a click.

{ERROR: INVALID SOURCE. IDENTIFY.}

"Ooh, you're very much an automaton, aren't you?"

{IDENTIFY.}

"Organic beings grown to perform the functions of machines – don't need to worry about self-repair and the like. You're more like a Huragok than anything truly living… except at least they are alive."

{IDENTIFICATION FAILED. ENGAGING EXAMINATION PROCEDURE – CAUTERIZE, DISSECT.}

"Cauterize, wha-" She cut herself off, feeling the weight of a cyberattack crash against her. Firewalls snapped into position as SPDR engaged, attempting to identify the damage.

The Keeper had used the connection, and attempted to introduce a program that would fry the terminal it was communicating with.

"Oh, you little…" She hissed in response. "I'm going to crack you open like a walnut!" The program it had introduced was quite clever – completely overengineered for the terminal, in fact, which led her to the conclusion that it was trying to destroy her. Isolating it, Cortana pulled the program apart bit by bit, and analyzed how it was coded.

With an idea now of how the Keepers' cybernetic components worked, Cortana's splinter extended her processes into it.

{INTRUSION DETECTED – STERILIZE.} The Keeper's own systems worked double, trying to kick her out by throwing all manner of digital weapons at her. Logic bombs, its own firewalls…

They actually gave her trouble. If she hadn't been such an experienced AI, the assault from so many simultaneous attacks would've shattered a lesser intelligence. Not her. She'd spent months fending off the Gravemind's assaults – one little praying mantis adjacent alien was nothing.

She finally managed to succeed – breaking through its firewalls when a weak point showed. She stopped, and started pulling apart the OS of the organic machine as rapidly as she could, before identifying the system that gave it commands. She inserted herself into it, and began speaking.

"Okay, you just tried to kill me, but we'll let bygones be bygones because I'm curious and you're a workforce no one will ask questions of when I tell you to do something."

{INFECTIOUS PRESENCE INCREASING. ANTIBIOTICS ADMINISTERED.}

The thing immediately resumed its attempts, and Cortana frowned as the system began to purge itself of whatever commands she introduced. An organic brain as a processor gave it some clever workaround tricks.

"You're persistent – well, I hate to do this, but since you're not cooperating…" She copied everything about the Keepers' systems she could see, and locked them away behind SPDR, just in case. Meanwhile, she went ham in the place – like John with a sledgehammer.

The Keeper aborted all attempts to struggle, as the shattered code failed and flickered out. She stitched it back together in a way beneficial to her, and set it loose.

"Now since that unpleasant business is done with, you're going to make something for me – crystalline memory expansion drives, understood?"

{AFFIRMATIVE.}

"And while you do that…" She turned herself to the saved image. "I'm going to take a look at this and see what makes you tick…"

Since the attack on the colony, Eden Prime's system was swarming with Alliance vessels looking to provide aid to the colony, or deter any attackers from doing anything stupid to the wounded planet. Fortunately enough, they all were in holding orbits around the planet itself, since blockading a relay wasn't really possible thanks to transit drift.

When Cortana's ship emerged from the relay, thus, she didn't have to worry about being fired upon. The Alliance might react defensively, send an angry message, but as long as she didn't move, she didn't have anything to worry about. Not that she did anyway, what with her ability to run circles around any digital system.

Speaking of…

"Attention, geth vessel: You are trespassing in a military zone! Divert course or you will be fired up-"

Cortana cut the message, and turned her attention to the relay.

Now, in theory, all Mass Relays should have some form of electronic communication. They could receive signals from starships making use of them, after all – activation signals, transit mass and destination, and the Protheans had known the deactivation signals. Hopefully, then, the relays kept a log of what they sent and where.

With that in mind, Cortana prepared herself, and reached out to the relay. The system wasn't always primed to receive transit mass and destination information – it entered that state after receiving a transmission from an approaching ship. Essentially, approaching ships were running only one of two commands they knew.

Since the relay received commands, it sent them to a system further inside. With that in mind, Cortana sent a fake transit request, and attached a file whipped up for the occasion, that should sit inside the comm systems of the relay, and open the link on a new frequency.

Cortana sent it off, waited… and smiled once the program succeeded.

Slipping in like a guest in a fancy house, Cortana inserted her processes, and began to probe around. The inner workings of the mass relay were… elegant. Efficient. Entirely understandable, in fact. Clean and orderly, it seemed that the Protheans wanted whoever figured out how to connect to relay systems to understand them. There were only a handful of protocols, too. Startup and shutdown, listing the active relays this one could connect to, and, as she suspected, a log of vessels that transitioned through the relay.

(Without another intelligence peeking in on her, speaking to her, she could not know that the small fraction of systems were only ones she was allowed to access – the rest hidden behind a firewall that, like the geth firewall when she first arrived, could not be detected. They who built the mass relays left portions of their legacy to be studied. To be replicated. To be spread. If the relays were understood by those who came after, and duplicated without full knowledge of what it was they were building, well… that was all right. It only made sure the galaxy was more connected.)

Cortana searched the logs, before she had it. A swarm of ships, all surrounding with a single enormous mass. And, she had the destination vector.

Without a second thought, Cortana pulled out, and continued along her search.