Although not mandatory for getting the HZFW Riverwatch War Chest, this quest is best approached after you unlock the Vine Cutter and the Igniter via story progression because Firewatch is, in fact, an old fort, and inside, you’ll find a Metal Flower and a Firgleam.
If you don’t have these two Special Tools, you can still complete A Tribe Apart quest, but you’ll have to visit the fort later to unlock the hidden areas behind the Metal Flower and the Firgleam.
So, throughout the guide below, we’ll go over the location of the War Chest Aloy has to recover and keep all spoilers to a minimum.
Horizon Forbidden West Tribe Apart Side Quest – How To Start
Horizon Forbidden West A Tribe Apart quest becomes available in Plainsong, in the second area Aloy gets to explore while traveling west.
You can see the exact location on my map above, and when you reach it, you’ll have to talk to Emboh, an old farmer.
Here is the NPC you’re looking for.
After talking to Emboh, you’ll be sent to find Jaxx in a cave south of Stone’s Echo.
Assuming you want to speed up the side-quest, you can skip the discussion with Emboh and head directly to the cave marked below to find Jaxx.
Once you talk to Jaxx inside the cave marked on the map, you’ll find out that he wants to help some Tenakth, their leader being Sokorra.
Since the Tenakth warriors are far from home, you’ll have to find a War Chest with some supplies. Although the story is bigger than this, as promised, this is a spoiler-free guide.
So, your main objective here is to get inside Riverwatch and find the War Chest.
Horizon Forbidden West Riverwatch War Chest – How To Loot
As you can see on my map below, Riverwatch is east of the cave where you meet Jaxx and Sokorra.
Upon talking to Jaxx and Sokkora, cross the river and then clear Riverwatch.
Now, you’ll have to get inside and get the War Chest.
So, approach the building from the east (location marked on my map above).
Next, use the Pullcaster to destroy the wall in my screenshot below.
Once inside, cross the basement, take a right turn, then a left one.
Now climb the ladder and do a back-jump (O on your controller) to reach a corridor.
Head right, and you’ll reach a courtyard. Once inside, if you have the Vinecutter remove the vines by dealing with the Metal Flower.
If not, head towards the stairs on the other side and head left, going around the balcony.
While on the balcony, look for a crane and a suspended platform.
The trick here is to shoo the clamp and release the platform, which will fall on the building below.
When this happens, it will destroy a wooden wall, revealing a crate.
Grab the crate and move it close to the broken wall on the opposite side.
Jump on it, then hop on the roof, heading towards the large gate in the distance.
As you can see in my image below, you can use a Grappling Point to pull yourself up.
Jump, then double-tap X, then while on the Grappling Point, head left.
Go around the corner, then pull yourself up on the large gate.
Great, now cross the gate, and when you reach the other side, look up to spot one last ladder.
Jump, then double-tap X, then climb the ladder.
On top of the tower, turn around to see the Riverwatch War Chest you have to loot.
Simply pry it open, then get ready to rappel down as the Horizon Forbidden West A Tribe Apart quest continues, and things get pretty intense.