What's Yours is Mine
An extended side quest in
Start by examining a fallen civilian.
You'll be knocked out by the same thief that attacked him. Bayek resolves to follow the tracks to the perpetrator.
This leads you to an investigation area in the (metaphorical) shadow of the Tomb of Menkaure.
Talk to the child scavenging in the ruins.
Pulse scan to find another investigation point- an entrance too small for you.
Go around to find another entrance, this one blocked by stone bricks you can carry away.
Move enough to gain entry (depending on your angle of approach, this may be all of them), and talk to the child inside.
She reveals that your valuables have been stashed inside Menkaure's pyramid.
Enter through a tunnel very low on the north side of the pyramid.
Go inside, then down the ramp to find the main treasure room.
Loot it thoroughly, then follow the passage down for another treasure room, and a cutscene.
Here you learn that the thief-children are cats-paws of bandits, who have taken their protector hostage. Listen to this tale, then loot the room. Note that there is some silica here, and one of those snake-hiding urns.
Retrace your steps back outside, but just before exiting the complex, take the small tunnel just above the exit instead.
Light an arrow to dispose of the wooden ceiling at the end of the tunnel.
Inside you'll find even more loot, and the stone tablet for this tomb.
Reading the tablet completes the location, and grants an ability point.
Exit for realsies and follow your marker to the bandit camp.
There are tons and tons of arrows in this location, so feel free to snipe the forward guards.
It's only once you enter the camp's perimeter that this is revealed as the Adorer of Thoth Tomb.
The bandit encampment here has many high ledges, both wood and rock. Use them to move through the camp unobserved. You'll have to pass by later with an NPC, so it's best to exterminate all hostiles as you go.
Clear the camp and press on. A vaguely circular stone tunnel will fetch up at a statue of Baba.
Behind the statue is a small pool. Dive in and swim forward (this isn't strictly relevant to your quest, but you might as well loot the place while you're here).
You'll emerge in an extremely bone-centric chamber. Scour is for silica and loot before returning through the pool.
Continue down the tunnel to find Anta, the dog, caged.
You can now return to the children, but if you want to claim the tablet here, you'll need to use the platforms.
First, load the lower platform with three spools of rope. Leap up to the high platform, and take the (minor) loot from the chamber here.
Remove the spools from the lower platform, and place them not-quite-under the high platform- you want them just close enough that Bayek will be able to pick them up without stepping off the platform when it descends. A little marker on the floor tells you where the edge is.
Jump on the high platform to lower it. Two spools will keep it down without Bayek standing on it, but add three more to keep it down for good. Now leap across to the newly risen platform.
This leads to an exceptionally rich treasure room.
Read the tablet to complete the location, and earn an ability point.
Return to the patient Anta, and exit the camp.
You don't actually have to take her all the way back- the children will meet you in a cutscene just outside camp, and reveal the existence of the boss horseman who has terrorized them thus far. You can either lie in wait here, or hunt him down among the pyramids.
If you do chose to hunt him down, remember that he's on horseback, and will move around the area pretty quickly. Still- there's nothing special about him as a fighter, just be sure to bring your own horse along, and hunt him down. The predator bow works nicely.
Confirm the kill to find the lost notes.
Return to Corteseos, who's pretty much where you left him.
Speak with him for an extended cutscene that ends the mission.
Anta lingers around just a bit longer than all the others, to say thanks. I think that's nice.