Engebret Tunnel.

It's a place with a lot of history behind it, dating back to the earliest days of Humanity's colonization of Rubicon. It had served a lot of purposes over the years. First, it was a long and mostly vertical crevice underground, extending a few kilometres or so, which brought it considerable interest from scientific parties looking for an easy way to check the geological history of Rubicon.

Then they had discovered how mineral rich the place had been, and so engaged in one of the first large scale industrial operations that had taken place on Rubicon. Engebret tunnel had fed the initial stages of planetary construction, sheltering thousands of souls within while infrastructure had been set up elsewhere on the world. A decently sized chunk of the Xylem's crew had passed through the Engebret Tunnel and its attendant facilities when the Xylem was deactivated.

Of course, the fact that the Engebret Tunnel had been located out in the Ice Fields meant that it hadn't been able to keep up with the rest of the planet once full industrialization had been underway. The place had ultimately been decommissioned, stripped down to a bare few internal facilities, and then basically left alone.

The PCA had been the final ones to lay a claim on the place; building a sensor near the bottom of the tunnel and some minor fortifications, then calling the place a Watchpoint.

Which, honestly, checks out. It's not an easy place to get to, and the entrance put a pretty considerable limit on how large the equipment that went inside could be.

By the time you could visit the place in Armored Core 6, it was long derelict, but also slated for restoration by the reactivating PCA. In turn, that meant the Corps, Balam in this case, wanted you to go in and blow the sensor up before the PCA could make anything useful of it.

As the mission unfolded; you would do so- and then you would very quickly turn around and skedaddle out of there because it turns out that blowing up the sensor would accidentally send a Coral deposit into a Surge.

Every single second you spent in that tunnel would corrode your AC's armour, and you'd also have to dodge Coral Flows that blasted through the earth, rock, and metal of the Tunnel lest they turn your mech into a lesson on high energy physics.

Once you were out, the entire place would explode, wrecking everything inside the tunnel.

In the game, all of that was a relatively simple mission. In life, though...

I was quite familiar with the properties of Coral. What was in the game a series of sequenced events waiting for flags to trigger was for me a scientifically studied set of phenomenon. Translating from one to the other, and then working backwards?

That had to be a rather large amount of Coral under that Tunnel. It'd be smaller right now since it was missing two and a half decades of Convergence and growth, but it still had to be there. It never would have Converged there unless there was already a decent supply underground. How it had gotten there was a better question, but the Fires of Ibis had led to much weirder shit being buried, so whatever.

The follow up to that, though, was the PCA side of things.

I might not have been as intimately familiar with Human technology as I was with Coral, but I was pretty learned when it came to that side of things regardless.

One thing that marked modern Human tech was just how durable and robust it was in the modern day and age. Planned Obsolescence was not a thing anymore, with materials science having gone so far it could produce the kind of megastructures like the Vascular Plant and the Grids as part of standard industrial efforts, to say nothing of the sheer inertial and kinetic effects demanded from modern war machines. Machine breakdowns were not common in this day and age, and it took some pretty fucking severe damage to break shit.

Time hadn't broken the place, in other words. Not within just twenty-ish years. Something else must have- though I didn't know what. It wasn't like this place was a geologically active area or anything.

The other question was when.

That's what made going to check out the tunnel risky; it was entirely possible it was currently active.

Which meant that I had to make a bit of a safer play, here. If it was still active and it did detect me, then I at least wanted enough time to either vanish or to take it out before it could send a warning. Secrecy and a complete lack of knowledge about me was my greatest advantage right now, and I couldn't afford to waste it.

That meant I was going to have to time a visit to coincide with one of the storms that circled Rubicon. I'd gained enough data from the communications facility to be able to predict those, thankfully. It wasn't too difficult; those storms were the Converging remains of Coral which had formed into superclusters. Take into account the effects of Convergence that they had onto each other, and I was confident that my margins of error would only go for about ten to fifteen seconds.

There was actually a smaller storm cluster trailing directly behind the one that had already passed. I couldn't make use of it for two reasons; first that it was a bit too small for me to be comfortable with, blocking out only about an hour and a half; and second because it would arrive and pass before I could get the drillship there, coming around in four more hours.

The next storm that would cover the area was about a month out. I could easily make that one; travel time was a mere few days at a relatively safe speed.

Which... actually worked out pretty well for me, honestly. Getting to Engebret Tunnel was one thing, but extracting and storing the Coral was another. I did not, currently, have the setup for either of those things.

Since I already needed to set up a small base of my own anyway... well, why not kill two birds with one stone? It's not like I had anything else I needed to do during that time.

The blindspot I eventually ended up picking was a smaller one in the deeper parts of the ice fields. A mountainous area, difficult to access due to irregular terrain, but enough crevices around to hide things from aerial inspection with a bit of work. The only problem with it was the distance to the Engebret Tunnel, which was about five days of travel, but with any luck I'd only need to visit there once.

I didn't expect to see the PCA there. It really wasn't that big, and the terrain just wasn't that great for a base. If not for the fact that the drillship could be used to displace massive amounts of material with ease, then I probably wouldn't have been able to use it either.

I was going to wait at the station until the second storm came around. The site was far enough out that transmissions would have been less than secure, so I was going to do my best to install some equipment here subtly that would let me stay in contact without going through the old network. It wouldn't take that long. I had all of the components I needed already in storage.

After that, though? I was going straight over.

Nothing to it but to get to it, I suppose.

I left the communications station five hours later. On the outside, the station hadn't changed. If one looked closely inside, though, they'd find that the main terminal now had one extra set of cables coming out of it, which went through the walls and floor. Most wouldn't think anything of it, since there were already other cables going through different portions of the station.

If they followed those cables, they'd eventually find some relays not connected to the main network. But, I'd buried those below the rest of the station. They didn't have a great range even with Humanity's various communications technologies of the modern day, but it was enough for me to stay in contact so long as I was in the ice fields.

I left before the storm was even over.

I'd arrived at my chosen blind spot to find out that I had been right about the PCA not being there. I checked the area pretty thoroughly anyway, spending enough time on it that when I had finished, the night had faded as the local star edged its way into the sky.

Once I was sure it was safe, I didn't waste any more time. I deployed all the bots, set out all of the equipment I had on hand, and then I had the drillship clear as much space at the bottom of a crevice as I reasonably could.

It worked surprisingly well, actually. A lot of the material I cleared could just get packed together and used as some makeshift cover for the entire place. Couple that with some tactical snow redistribution and a few higher-tech solutions, and I could make a facility that was, for the most part, undetectable.

Well, undetectable to the average, common methods, at least. It would hardly stop in-depth surveys or ultra-high sensitivity scans like gravimetrics or omnispectrums, but those were rarer, specialised equipment that you only bring out if you're already looking for something. The PCA had no reason to be that thorough, not when they were under the impression that they were only ones with a presence on the continent.

I had everything up and running in a few days. Securing resources took a little longer, unfortunately. The three main options that Humanity took to achieve that, Mantle Taps, Nucleosynthesis Plants, and Large-Scale Mass Sifting, all weren't options for me, but I still had the old options of scan and dig.

Turns out I had a pretty good spread of the essential stuff within a relatively short range. The drillship was pretty well suited for actually getting to them, though it took a bit more finagling to actually extract it. For the most part, I dug a big pit, then tossed all the raw ores and stuff in there for the MTs to sort through later whenever the processing setup had finished a load.

I'd had barely a day to spare by the time the drillship was ready to go and recover the Coral, so I had it leave the place and every strictly necessary bot behind to continue working on the rest of upgrades I was planning to make.

Most of that headstart had then been spent on a slower, safer trip. I still arrived an hour before the storm was scheduled.

I felt the presence of the Coral from quite a distance away, a faint buzz at the edge of my mind, incomprehensible and quiet. I didn't detect anything else; no sonar pings, no scatter of electromagnetic fields that marked other sensors, which I hoped meant that the Watchpoint was already decommissioned, but...

I stopped there, just in case. Haste made mistakes, and I couldn't afford that right now.

The final hour passed slowly, to me, but it went regardless. The storm came again, and I counted down the seconds until I was sure it was safe to poke my head up.

Finally, it was the moment, and I sent the drillship to breach the surface.

I beheld a whole bunch of nothing. The entrance, from a glance, was quiet, dead. I sensed no activity.

I waited another minute, and then activated the long range radar, sending out a few short scan bursts. I got back a whole lot of inactive machines, most of them damaged.

Oh, that was relieving.

Alright. Drillship, back underground. Set scan off, bottom of the Engebret Tunnel is about where I'd expected it to be.

And... go.

The drillship approached slowly, just in case. The buzz grew stronger as it came closer, becoming more and more comprehensible to me. It was...

Actually, it was a little strange. There wasn't just the background communication of the various organisms in the colony. There was... something else. Something more. Almost a data flow, with hints of an order and structure that I didn't understand. It was... another wave, interspersed in the mass.

The drillship continued to approach. Some of the noise started making sense. The colony was a healthy one, I understood. Growing well. That other wave shifted, changing. That was still outside of my understanding.

The drillship came close enough. The Coral resonated, and so I reached out and made Contact-

Something reached back.

The factors resolved. The wave was not just a wave.

It was a presence.

"Oh." I spoke.

How terribly embarrassing. I really should have put that one together much quicker.

I smiled, nonetheless. "Oh, how long I've waited to hear a voice that wasn't my own."

The presence shifted. The wave pulsed. I saw and felt the Coral spark, little bolts of lightning running through the air.

"You... You are... Mother ?"