Shadow of the Tomb Raider

This mission will not be offered until you have reached the Skull Cave in the Hidden City. You must also complete "The Age Makers" side mission from "The Pillar" DLC. (Not sure what happens if you don't have The Pillar installed). Once you have done that, go speak to the boy sitting next to Q'orianka at the bottom of some stairs. He will say "Hello" and then Q'orianka will give you the side mission.

Before you can complete this side mission, you will have to equip the Serpent Guard outfit. You can either put it on now, or wait until you have to. You will also need to prepare for combat against cultists.

The side mission begins at the temple on the west side of the city. Your quickest way there is to fast travel to the Temple District base camp. When you get there, you may notice a man and woman standing in front of an axe climb to the right of the temple entrance. They're blocking your way! Go find the shirtless man wearing a headband sitting on the steps, in everyone's way. Talk to him. When your conversation is over, the man and woman by the wall will move. Now you can climb the wall and proceed. Examine the little stick barrier in front of a hole to continue the mission.

After a swim, you'll confront two enemies who are easy to kill stealthily. Proceed a bit further to a more substantial combat section. You will start out in stealth with 6 enemies to kill, and then you'll be spotted and some more will come out. Kill them, proceed past a couple of traps, and pick up an object that concludes this part of the mission.

Lara will transport back to the temple area. You need to go to a spot north of there. It should be marked on your map. You're looking for a small pool enclosed in stones, fed by a tiny waterfall. Examine the waterfall. Somehow, you're going in there for the next part of the mission. Make your way into the puzzle room, with the waterwheel. You need to lower the water level, engage the spiky gears, then use the spinning cylinder on the top to seal the room and raise the water level so that you can climb out. Examine the chest to conclude this part of the mission.

Now you need to go to the abandoned village. You may remember this area from the first time you met Itzli and Unuratu or from the "Ancient Studies" side mission. You could fast travel to the Abandoned Village base camp, or just slog your way there because you're pretty close to it anyway. As soon as you come down the steps, jump up into the building on your left. Tether across and enter the challenge tomb.

Complete the Sixth Seal challenge tomb. This will unlock:


Lara is back in the abandoned village. Fast travel to the Temple District base camp and talk to the so-called "old man" (who looks the same age as all the other men) you spoke with earlier.

You just have one more little task. Go to the bridge leading to the cult area. You can fast travel to the Paititi Market base camp, or just go your own way. This is where you have to wear the Serpent Guard outfit. Give the disc to the dude on the bridge. All that's left to do after that is return to the Skull Cave and talk to the boy, who has nothing to say to you this time, not even "Hello," so that Q'orianka can shoo him away and talk to you. Poor kid.

Your acheivement will unlock here, and you will receive the Silent Sting - Scorpion pistol and Hunter's Array - Apex outfit, which you need to unlock:


Please let me know in the comments if I left out something important. That would do more good for the community than an uncommented downvote would.