Into the Ancient Angaran City
This quest will begin automatically after you finish the quest "Remove the Heart", which is just as well, as before that there’s a barrier around Ja Niihk. At the eastern end of Voeld there are three Forward Stations in a line. Fast travel to the northern-most of the three and drive southwest to reach the northwestern edge of Ja Niihk, where you’ll find a trench leading into the frozen bowels of Voeld.
Descend down this trench and move from healing rod to heating rod until you find a crevasse to the east you have to leap across. Do so, and from the walkway on the eastern edge of the gap turn northeast and leap another gap, then head east and dispatch some Kett; an Anointed and a Wraith. After they’re dead continue east, then southeast and drop down a series of ledges and continue following the linear path ahead. Eventually you’ll reach a doorway, beyond which you’ll find another Anointed/Wraith pairing. Beyond the door head southwest, then turn southeast through another doorway.
When you reach a fork, continue east, southeast, as the other path shortly leads to a dead end. Go through another doorway and continue southeast to find yourself on high ground overlooking a large chamber filled with Kett… Chosen, anyways. Drop down the ledge and kill the Kett, then note your surroundings. The rest of this area basically forms a loop, with tunnels running to the southeast and northeast from this chamber.
Head southeast first and turn east, northeast when you must to reach a fork. There’s a small room to the north, northeast, but there’s nothing of interest there, so turn southeast instead to reach a chamber with another handful of Kett for you to slaughter. Once they’re dead, turn east, southeast to find a captive Angaran. Looks like this just turned into a rescue operation.
Deactivate the Console near the Angaran’s cage to free the alien, then turn northeast and continue in that direction until the tunnel turns northwest. Unfortunately there are more Kett down the slope to the northwest, including a number of Chosen led by an Anointed. Defeat them and look around to find two more captive Angara in close proximity; free them both, then talk to the Angaran Captive that waits around for you. He’ll tell you that the Kett were trying to get behind a nearby wall, and had the Angara stacking explosives for that exact purpose. In fact, they apparently got far enough along that all they needed to do was strike a match… figuratively, of course.
Buried in the Ice
Awfully convenient, but who is complaining? Venture a ways to the northwest, then turn northeast to find the Kett explosives. What is behind that ice that they want so bad? Doesn’t matter - if the Kett want it, it’s probably best that you get to it first, whatever it is. First, however, ascend a hill to the west, northwest and follow the tunnels beyond until they deposit you at a doorway to the northwest. Head inside and leap behind some Kett crates along the western end of the room to find an Angaran Artifact . Scan it, then collect it - it’ll be part of a quest you’ll start later, but there’s no harm in grabbing it now.
Backtrack to the explosives, scan the "Frozen Water" (on Earth this magical substance is called "ice") and after some chatter retreat to the southwest so the ice can be safely blasted away. Go through the newly-cleared tunnel to reach a large chamber housing a more sordid technological relic from the Angaran’s forgotten past. The AI will try to lie to you - and for good reason, as Milky Way folk are historically wary of AI - but sadly, your own AI (hypocrites!) will call her out on her lies. How do AI have genders, anyways? Whatever, the female AI will continue to lie until one of the overly inquisitive Angaran captives gets himself in trouble, prompting the AI to offer a deal, a life for a life. Make your choice, and if you chose to apprehend the AI at the cost of the Angaran’s life you’ll then have to make another choice; turn the AI over to the Angara, or allow SAM to be its custodian. Whatever choice(s) you make, when you walk away this quest will end, earning you 29 AVP, +2% Voeld viability and 1,330 XP.
This quest is over, but there’s one more somewhat related thing you can do before moving on, and indeed, it provides a fine transition into the next part of this section. Return to Techiix Station and talk to Eska Yeveth, who sports a shiny new quest icon. Despite that, she doesn’t actually start up any new quests. She does, however, invite you to find Voeld’s vault, restore the climate, and deploy an outpost on the frozen planet. As far as diplomatic harmony goes, what more could you ask for? It’s now time to see to the mostly neglected southern bits of the map, including the quests "Settling Voeld" and "Restoring a World", which is much more interesting…