Hidden away in remote locations on the ocean floor, these ancient alien structures were key strategic points during the Second Alien War. Once used by the aliens to communicate with their stellar cousins, they were sought out for the great power that lay dormant in their deepest recesses. Within one of "Artefact Sites" was a Synomium Device of incredible power. These devices were different from the ones found in an Alien Colony, for their combined power would extend the aliens' Molecular Control network across the entire planet. This alarmed X-Com greatly, knowing that if these sites were successfully activated, the alien army would become invincible. Finding and destroying the Artefact Sites would tip the scales in favor of X-Com and put the aliens at a serious disadvantage.
Artefact Site MissionEdit
The typical Artefact Site Attack is in many ways the same as an Alien Colony Raid, with the exception that they randomly occur like a Terror Attack or Ship Raid. The mission is divided into two sections, one on the seabed, and the other within the interior of the base.
Section 1: SeabedEdit
The layout for the Artefact Site surface is rather confusing, with plenty of hidey-holes for the aliens all around. There are many pyramid structures, some are for looks, others that have sniper posts accessed by grav-lifts. The entrance to the interior is in a pyramid with a rectangular base. Tasoths and Aquatoids will be your opposition on this mission(hey, that rhymed), and they are backed up by Hallucinoids and Tentaculat. Considering the site's stategic importance, expect the aliens to be carrying heavy weaponry(Sonic Cannons, Disruptor Pulse Bombs and Thermal-Shok Bombs). Since there will be Tasoths and possibly high-rank Aquatoids, your troops will be at the mercy of a Molecular Control Maelstrom. To advance to the next section, you must A. get all Aquanauts to the green glowing entrance and hit the "Abort Mission" button(the one with the Triton sub taking off), or B. kill all aliens in the area(not recommended).
BE CAREFUL!! Any items left on the ground on this stage(even the stuff in the transport) will not be carried over to the next section. Grab all the equipment that you might need before advancing, or you could be in trouble. This also counts for Aquanauts not in the entrance zone. Depending on what happens, they'll survive if you win and be counted as MIA if you fail.
Section 2: Base InteriorEdit
This part of the mission is like the Alien Colony interior, except that the doodads look like stereotypical sci-fi machinery with a gold paint job(but the Ion Beam Accelerators there look kind of like boilers). There are lots of halls, alcoves and storage rooms, some of which are used by aliens to ambush Aquanauts passing by. The goal is clear and simple: find the Synomium Device, destroy it and get out alive. Oh, if only it were that simple, but then Terror From the Deep would be too easy. Anyway, the place is crawling with Tasoths and Aquatoids that are prowling the halls with plenty of Sonic-based ouch to go around. Tentaculats are plentiful here, and will be happy to feed your troops to their babies. The entrance to the Synomium Device chamber is not hard to miss. It is a 4 X 4 grav-lift within a giant pillar in a wide open room. The room is guarded by Tentaculats and alien snipers. I would recommend using a Submersible Weapons Platform, like a Coelacanth or Displacer, to breach the defenses, for it is immune to the Tentaculat's zombification, allowing it to draw attention away from your Aquanauts. Upon reaching the chamber, you'll see the device, a small module near two pillars directly in front of the grav-lift's exit. Plant an explosive of any kind to destroy it quickly. Once you've destroyed the device, how you handle the rest of the mission is up to you. You can finish the aliens off for collecting loot, collect as much alien corpses and weapons as you can and get out or just drop everything and run. Even if you lose all of your soldiers, if you've destroyed the Synomium device, the mission will still be a success.
Possible loot (minus aliens and weaponry) includes ten Ion Beam Accelerators, 1 Sub Construction, twelve Cryogenic modules, a Learning Array, two Implanters, 484 units of Aqua Plastic and three Re-Animation Zones.