A Dying Planet

After you saved Kiiran Dals' team from Remnant Stasis, she mentioned that Havarl was in decline. Though Havarl appears to be thriving, not everything is as it seems.

Acquisition
This mission is automatically received after completing Helping Havarl's Scientists.

Talk to Kiiran Dals about Havarl's problems
Kiiran Dals says that Havarl is having issues: uncontrolled mutations in the wildlife mean that the ecosystem is crumbling away. This appears to be an issue of having only two working monoliths. Torvar, one of the researchers, suggests asking the sages at Mithrava. Kiiran Dals scoffs at the idea, explaining how the sages are hermits that believe in isolating themselves from modern thought.

Find the entrance to Mithrava, the sanctuary
Regardless, you will need to go to Mithrava. Head to the southernmost part of the ravine to find a Remnant door. Once through, continue all the way to the back of the room to find a Remnant console; it will appear out of the ground on your approach. Interface with it to open a nearby wall.

Reach the top of Mithrava
Through the wall is a short corridor, at the end of which a pillar rises. Climb the pillar and head up through the hole. Use the gravity well to cross to Mithrava Ascent, evidently a tall Remnant tower. Use another gravity well to head up; once you land, go out the door.

The path forward is to the left of the exit; drop down from the ledge. It appears to lead to a dead end, but interacting with a Remnant console brings down a platform. Use the pillars on either side to reach it, then jump from the platform to the pillars across the way. Continuing on will lead you to another Remnant console; using it will activate a bridge for you to cross. There are a few Remnant on the other side, so be mindful of the edge while fighting.

At the end of this ledge is a short pillar for you to jump on to reach the next level. Keep moving until you see yet another pillar and climb it to reach a Remnant console. Interfacing with it activates another bridge. Cross it and climb up a few consecutive pillars and ledges to reach a Remnant door, which opens to another gravity well that takes you upwards and finally to Mithrava itself.

First Sage Esmus comes to ask how and why Ryder is here. However, once informed, he says that restoring Havarl is impossible, because they do not have the knowledge of the third monolith or the vault. It is explained that angara believe in reincarnation, and that sometimes memories of a soul can be remembered via familiar items. Zorai, an ancient champion of the angara, was said to have knowledge of the Remnant; however, the soul has been reborn in Taavos, a member of the Roekaar. Esmus gives Ryder the location of an item that belonged to Zorai.

Before leaving the area, you can grab a memory trigger for Ryder Family Secrets. You can also pick up Task: Unearthed from Sage Fleera and A Lost Sister from Sage Amurd. Remember to deploy the Forward Station.

Go to the location Esmus mentioned
Heading to the marker on the Havarl map, you'll run into Remnant and likely some hostile wildlife as well. Past them, you will find a large Remnant structure, and SAM will notify you once you are close to the location Esmus gave you. More Remnant will be here, as well as a Galorn, though the latter can be avoided if careful.

Locate Zorai's heirloom
Enter the Remnant door and take the gravity well down to the Remnant Abyss. Moving forward, you find a Remnant console on a small island platform. Interacting with it causes all three walls of the room to come down. Remnant will attack from the left wall from the console, so be prepared.

The path the Remnant came from is a dead end, and the path straight ahead is blocked by a barrier and a gap, so head to the path from the right of the console. Be ready for more Remnant just around the corner. Continue until you reach a door, which leads to the area north of the Remnant console you interfaced with earlier; here you find a Destroyer alongside a few other Remnant.

Once the Remnant have been defeated, you can find a Remnant console to interact with on the eastern side of the room. It activates a bridge to the small separate room on the map, which has a container and an Adaptive Remnant Core Device (100 ). Continue north through the door until you reach a room with a giant pillar in the middle, surrounded by yet more Remnant, including two Nullifiers.

Once cleared, interact with the door towards the marker to reveal ancient angaran remains alongside a data drive. Searching the remains will give you Zorai's Heirloom, apparently a gauntlet of some sort. Examine the data drive for more information.

You don't need to backtrack from here. Instead, go to the side room and interface with the Remnant console, which both opens up the other wall for a shortcut back to the entrance and creates platforms on the pillar in the center. You can climb up the pillar for two containers before returning to the surface.

Go to Taavos' Roekaar Camp
Head to the marker near the ravine. There are Roekaar there, but they have activated the bridge, allowing you to cross once you defeat them. More Roekaar are waiting across the bridge, so be prepared. After clearing them out, go up the stairs; there is a datapad for Task: Roekaar Manifestos on one of the crates here. Go through the door to the Ancient Courtyard, where a forward station will activate.

Moving forward towards the marker will activate a Roekaar shuttle dropping in enemies. Once they are defeated, head towards the camp.

Defeat the Roekaar at their camp
As can be expected, the camp is heavily populated by Roekaar, as well as a few Challyrion. After clearing out the front, walk up the stairs to find the main encampment. More Roekaar are here, accompanied by Adhi.

Find Taavos
Once all enemies have been defeated, you can search the two empty buildings for Roekaar manifestos, one in each. The Archive System required to complete A Lost Sister is also found in this area.

Taavos is ready to die, but Ryder instead convinces him to hold Zorai's gauntlet. He suddenly gains knowledge of an underground monolith, along with emotions not his own. He reluctantly agrees to meet Ryder at given coordinates and lead them to the monolith.

Meet Taavos at the entrance to the lost monolith
Head to the northern end of the ravine and talk to Taavos. With his newfound memories, he is able to activate the Remnant technology to enter the cave where the monolith resides.

Walk with Taavos down the path; if you want to look around, he'll stop and wait for you to catch up. Urged by his memories, he takes a side path that leads to the remains of another ancient angara, along with an audio log.

Examine the remains
The remains turn out to belong to Zorai. Scans and the audio log reveal that she was female, something the sages evidently forgot.

Continue down the path with Taavos. He leads you to a gravity well, with the third monolith further down and away.

Activate Havarl's third monolith
Once you have landed, there's a Remnant console just ahead. Interface with it to activate this monolith.

Taavos says he will stay here, as he has much to think about. With all three monoliths active, Ryder can now head to Havarl's vault.

Before you leave, collect the Memory Trigger. On a ledge to the north east in the area you scan an Adaptive Remnant Core Device for 100 Remnant research data.

Find and activate Havarl's vault
Head to the newly revealed vault near Old Pelaav. There are a few Remnant near the entrance; clear them out and go in the vault doors. Use the Garivity Well.

Turn on emergency power
You'll need to turn on emergency power by interacting with the power console, though Remnant spawn and attack you the moment you do.

Lift the lockdown on the vault
On the high ledge is a turret. Activate it with the neraby console, and it will assist you during the esace from the vault. There are 200 Remnant research data close to the turret.

Jump down and discover a container with remtech, which will be accessible during the escape from the vault. SAM marks it on the map.

Several Remnant consoles are now available to interface with, although you must activate them in a certain order to proceed. Facing the door that you are trying to open, use the left console closest to the door, the left console further from the door, the right console closest to the door, and the right console further from the door.

The purification activation console is directly through the door; however, before starting the purge, go around to the other side to find another console to interact with. Solve the glyph puzzle presented in order to receive 2 skill points.

When you are ready, activate the purification console and run, although you can't run far, as the door closes on you and you have to fight off Remnant while the purification cloud approaches. The doors will open in the nick of time, although there are more Remnant in the next room as well; you don't have to fight them all, and if you activated the Remnant turret, it will help you. When the door opens you receive 367 xp (an odd quantity, but it's not from killing Remnants).

Run to the container on the lower floor behind the turret and collect the remtech.

Use the console on the upper level to stop the purge and successfully activate the vault.

You receive 1330 xp, 900 AVP, +55% Havarl viability (the xp doesn't show on screen).

Return to Kiiran Dals
Report in to Kiiran Dals at the Pelaav Research Station. Esmus and Taavos are there as well, having been influenced by Ryder's actions. While no outpost can be placed on Havarl, Kiiran Dals invites people from the Initiative to help the research station.

Aftermath
You will receive the email "Harval: Science Team Deployment" once you have completed this quest and return to the Tempest. Acknowledge it, and you'll receive the mission Cross-Cultural Alliances.

It is now possible to access a well hidden decryption puzzle (needed for the Cryptographer Achievement). Start from the second Forward station from the west. Go west and search for a cave in the southern wall. A Roekaar raider will attack. Inside the cave is a Remnant console, that wasn't there before. Interacting with it unlocks the way to the puzzle. Use the scanner to follow the cables to the east, and after a short walk it's time to jump up on those small platforms to a console on the top. It points you to a similar climbing structure to the west. On the top is a gravity well that takes you to the puzzle console. From the another gravity well take you to a container.

Mission Rewards

 * 1330 XP, 73 Andromeda Viability Points, 5% Havarl viability.
 * From previous objective: 367 xp.
 * From previous objective: 1330 xp, 900 Andromeda Viability Points, +55% Havarl viability.