Reaching the High Overseer Campbell's Office | Mission 2 - High Overseer Campbell Dishonored Guide
Last update: 11 May 2016
New Main Quest: Find Campbell and Curnow in the High Overseer's Meeting Chamber
New Optional Quest: Search the Archive for information on the Heretic's Brand, a tool for casting out Overseers
The nearby gate is locked, so you need to start climbing in the spot shown in the above screenshot. The game will suggest Blinking (teleporting), but this should not be necessary, because you can leap towards the more distant objects. Get to the upper balcony and listen to two overseers conversing about casting out (Heretic's Brand). This way you will obtain an important side quest, because it is connected with eliminating Campbell. Jump down and search the area for bolts and Sokolov's health elixir, but watch out for two overseers patrolling the area.
In order to approach the Overseer's building, you need to go around the gate seen in the distance. The obvious solution to this problem is to reach the precinct shown in the above screenshot. Be careful, because there is yet another overseer inside. You can also find food, bolts, spring razor, rewire tool, Piero's spiritual remedy and a note (Curnow's visit).
The less obvious ways to get over the gate are an attempt to Blink over to the other side, or Possess a random rat. If you do the latter, you will have no problems sneaking past the gate (the above screenshot).
Regardless of how you got past the gate, you should stop for a moment and take a look around, because there are quite a few enemies in the area. The main street is patrolled by four enemies, side alleys are watched over by two guards, and in the square right in front of the Overseer's building there should be three or four more. If you intend to go around the guards, you should make an extensive use of teleporting, but also keep your eyes open for spots where you can hide in shadows. If you, however prefer to eliminate the guards, try and pick the ones that stray too far away from the others for the execution to be noticed. You also need to remember to carry the bodies away into unlit and not watched places.
When you manage to get near the main entrance to the Overseer's building, you should also make sure to check out two basement rooms (the above screenshot). In the one to the left, you will find gold and Sokolov's health elixir. In the other one, you'll get the opportunity to overhear two guards talking in Campbell's secret room. Before you take any decisive action, finish the exploration of the premises to obtain gold, Sokolov's health elixir and a spring razor.