Finding the supply chest in the sewers | Mission 1 - Dishonored Dishonored Guide
Last update: 11 May 2016
New Main Quest: Find the supply chest in the sewers
Start exploring [Dunwall Sewers], by opening the closest gate. After you teach the blocked passage, collect food and a note from a friend, then start climbing by grabbing onto further chests. Your destination is the section localized near the ceiling. Go straight here and watch a very interesting cut scene featuring a guard and a small group of rats.
Follow the narrow passage until you wind up in a spot where you will be able to jump down to a lower level. Go straight here and reach a wider tunnel. Do not approach the rats visible to the right, or else they'll attack and there is no point in wasting ammo on them, because you would gain nothing. I recommend jumping into water right away and follow the current to reach the partially flooded tunnel shown in the above screenshot.
After you swim through the tunnel, get out of water and collect gold and Damien's Journal. Climb up the stairs and approach the body hanging on the cranking mechanism. Carry the body away (just drop it anywhere) and interact with the crank itself. Press and hold down the "F" key until a new passage opens.
Continue your exploration of the sewers and keep your eyes open for food on your way. You should be able to reach a much larger room with rats in it. You need to solve an easy puzzle here. Begin by reaching the central platform with bodies on it (the above screenshot). Meanwhile, you need to avoid the abovementioned rats, so try and jump over from one large object to another, and use ground only to run to the main platform.
Approach any of the bodies and lift it (press and hold the "F" key) and toss it (left mouse button) so it lands on the ground. This should draw the attention of the rats, which will give you enough time to reach another cranking mechanism and interact. Note - if rats attack you anyways, try and toss the next body even further away from the crank. If you, however "run out of bodies", wait for guards to throw further bodies into the sewer.
Press and hold down "F" key until you fully use the mechanism and go through the newly opened passage. After you find yourself in a wider tunnel, turn right and climb up the stairs. Look around the place for gold and food. Approach the chain and press "F" key to grab it. Start climbing it and press the "SPACE" key once you reach the upper platform to jump onto it.
There is a larger area ahead of you and while exploring it you will have to pay attention to two traps that activate whenever either of the vertical cords is touched. Start by exploring the surroundings of your starting place, as well as the lower level (for the time being ignore the stairs to the left and the corridor to the right) to find food and gold. It is also worthwhile to jump into water and examine the dead body floating there. Return now to the starting point and turn your interest to the upper balcony shown in the above screenshot. Jump towards the balcony and press the "SPACE" key to climb onto it.
Jump over the large pipe ahead of you to reach a place where there is a launcher connected with one of the traps (the above screenshot). Interact with the launcher to disarm it and acquire an incendiary bolt.
Jump over the pipe again and go through a plank with a skull painted at the end of it (the above screenshot). After you reach the end of the plank, jump over the balustrade. Look around for Sokolov's health potion and gold. You may also disarm the second one of the launchers and acquire another incendiary bolt.
Return now to your starting point. With both of the launchers disarmed, you may well cut the cord in your way (the "F" key) because you will come to no harm now. Choose now the stairs you ignored earlier, and ignore the other vertical cord. Explore the new area thoroughly and find gold. Finally, approach the supply chest shown in the above screenshot . Read to the Lord Protector and collect special equipment, i.e. Corvo's crossbow, Corvo's folding blade and Dunwall sewers gate key.