City of the Sun

Head to Meridian from its northern gate. Cross the bridge and you’ll be blocked by the Carja Guard commander. Fortunately Erend is nearby so after calling for him and asking him about Olin, he’ll welcome you to the city and escort you inside.

For now just follow him to Olin’s house. You’ll be free to explore the entire city later at your own leisure. After entering Olin’s house, use your Focus to scan the carpet. There’s a hatch inside so examine it up close for Aloy to roll the carpet and reveal it.

Next, head to the second floor of the house and find the stack of ingots by the ledge, above the hatch. Interact with the stack to push it down, breaking the hatch open. Go downstairs to the basement.

Use your Focus to scan the map and the journal on the table. There’s a hologram datapoint on the bench near the corner of the room. Scan it with your Focus to play the hologram and register it to your Notebook. Once done, examine both the map and the journal. The journal will be added to registered as a Datapoint > Scanned Glyph.

After checking out the map and journal, talk to Erend. When you’re ready to leave, Erend will ask for your help in identifying the exact people responsible for Ersa’s death. He said he’ll be waiting in Red Ridge Pass, which will be marked in your map. This will begin a new separate main quest, The Field of the Fallen.

To continue with this quest, you’ll have to locate Olin in the marked excavation area. Make your preparations and head there.

Note:

• Before hunting down Olin, spend some time in the city. Check out the specialty merchants where you can trade your Ancient Vessels, Metal Flowers, and Banuk Figures for extra shards and free mods.
• The other special merchants in the city include one that sells rare machine parts (usually used for trading for new equipment on top of shards, crafting, or quests)
• Another special merchant sells unconventional resources in exchange for shards and basic resources. These “special” resources can then be traded to another special merchant that trades normal resources for Resource Boxes.
• Visit the Hunting Lodge. There are new sidequests there and the chance to obtain unique weapons tied to your performance in all the Hunting Grounds in the game.
• If you haven’t visited the Meridian Village below, you can use the main city’s elevator to go down. There are new sidequests/ errands available there as well.

When ready, head to the excavation site east of Dimmed Bones and head inside. After the scene, you’ll have to deal with the two newly-awakened corruptors and cultists. The cultists on the ledges can fire long-range arrows so unless you’re good enough to snipe them with headshots, your best bet is by using the tightropes to circle around and stealth-kill them.

Next, you have to deal with the Corruptors. Since there are two of them, it will be better if you’re able to make proper preparations like placing tripwires and planting traps. Fire arrows will still be effective against them in heating them up and forcing them to reveal their weak point. Take note that Olin will turn his back against the cultists and will start attacking them as well, giving you a bit of breathing space.

After clearing the area, confront Olin and you’ll have a flashpoint whether you’ll kill him or let him go. Either way, he’ll beg for you to rescue his family that are still captives of the Cultists. This will start the errand “Collateral”. After deciding Olin’s fate, the quest will be complete.