Akra Garrison
A large fortress in central Alexandria, with two captains, a commander, and four treasures to find. Two are in the eastern building by the smithy.
This is convenient, because the area above that building is where one of the captains likes to hang out- but first things first.
Approach from the north, using the city buildings as cover, and snipe the wall guards (or assassinate them, if you can evade their view). Be sure to scan carefully- there are always more guards on the wall than you think.
Murder yoru way to the crossbow nest, where one of the captains is usually stationed, and take him out.
Work your way east along the wall. Do pause at least once to rescan the area for troops on the move, then wait atop the smithy building to ambush the other captain.
move a little farther along the wall, then drop down and enter the smithy from the northwest. Here you'll be able to refill your arrows, and see the window that'll be your entry into the building.
Use the shield racks and detritus here as visual cover, and make for that window. The first treasure is in a back corner on the ground floor, in a white box.
Go up the stairs for the second treasure- in a standard red chest.
A rope at rooftop level leads between this building and the central building. Cross it to get a drop on the guard by the training yard.
Drag his body inside and claim the third treasure, in a small red box on the far wall.
Happily, the last treasure is in the Commander's offices, saving you some travel time. Pop back up to roof, and enter through the upper level to give the Commander a surprise.
Loot the final treasure from one of his work tables to complete the mission.
Note that there is an optional objective here- freeing the rebels from their cages.
Like animals, you can also open the cages via arrow. Freed rebels will fight the guards, if you need a distraction or reinforcements. Freeing them all grants an extremely modest XP award.