There are a total of 5 Bone Charms that can be found in this mission.
#1) This one is located on the bridge by where you start the mission, behind a gate where the guards are dumping bodies in the water. There are three ways you can get this, one of which involves Possession. You can go on the bridge and possess a rat, then crawl under the gate and get rid of the possession to grab the Charm.
You can also use Blink to get across the ships in the water, then get onto the rocks and climb up the back way. Additionally, there is a pipe that runs the length of the bridge, connected to it, that you can use to get to the section behind the gate (the guards will see you).
#2) This Bone Charm is located in the area just past the first Wall of Light in the first area of the mission. Once you get past the first Wall of Light, there will be an alley to your right with two Bottle Street Gang members keeping a guy hostage inside of a building. You must take these two gang members out to rescue the guy. Once you do, head inside the building where he was and go to the other room here. There's a hole in the ceiling where you can climb up, which is where the Bone Charm is located.
#3) This one is located in the Dunwall Whiskey Distillery, which you'll go to if you do Granny Rags second side mission. Once inside, make your way past the two big areas until you get to the one with a lot of barrels. This Bone Charm is located on a rafter in that room; you will need to use the barrels sticking out of the wall to get to it.
#4) This one is located in the Back Yard area. After taking care of Campbell, you can get to this area by a door at the bottom of a nearby stairwell. The farthest building straight ahead of where you entered will house this Bone Charm. Normally, you'd need a valve that can be found in the Work Shop building, but there is a boarded up entrance on the far end of the building. The Charm is right next to a dead body.
#5) This one is also located in the Back Yard area, in a building on the far left side of the area. There are three buildings with vents connecting them that lead up to it, with the entrance being a window. Be careful as you step through the window, as there is a trip wire connected to a trap right inside, so hop over it and disable the device. There are chains on the left side of the room, leading downstairs, where a swarm of rats are crawling around. You must hop to the table with the vice on it and use it, which will free the Bone Charm that was trapped in it.
