Open the passage through the fireplace | Walkthrough Black Mirror Walkthrough
Last update: 08 December 2017
After getting back from the castle, talk to granny sitting on the couch. Then examine the message above the fireplace written in blood and the doors inside it. In order to open the passage, you'll have to press the rune tiles in the right order. However, since we don't know which runes to press, you should exit the zoom.
Go through the big door to the left and enter the old wing of the castle, where Margaret went.
Before talking to her, check out the rune on the wall to the left, which was previously obscured by the emblem - it's identical to one of the runes on the tiles (a piece of paper with a drawing of the rune from the old wing will appear in the equipment). Take a look at the globe on the desk (highlighted above) - the protagonist will notice that something was marked down near Australia. Then talk to the granny about everything you can. After this conversation, you will receive another piece of the key (to the housekeepers office).
Having gotten back from the armor room, go to the hall and take the stairs up to enter the office. Zoom in on the globe identical to the last one (on the desk, slightly to the right). This time, Spain is marked.