Dishonored

In Mission 3 (House of Pleasure) Find Slackjaw in the distillery. Help him obtain the combination to the Art Dealer's safe. If you rob the safe before handing the combination over, you can unlock the following achievement as well:
Even if you rob the safe first, give the combination to Slackjaw afterwards.

Also, make sure to let Slackjaw take out the brothers at the Golden Cat. You'll also need to do Granny Rags' side missions in order for this achievement to be available to unlock in mission 7.

In Mission 7 (The Flooded District) You will come upon a thug lying against the wall in the sewer. Talk to him and a new objective will appear. After talking to the thug, follow the objective marker that says "Sewer Key." Upon arriving, you will see Granny Rags and Slackjaw in a cave. You'll see that Granny Rags has made Slackjaw her bitch. At this point, create a new save file so that you may reload it and earn the Granny Rags side mission achievement after finishing Slackjaw's.

Talk to Granny Rags and she will ask you to kill Slackjaw and throw his body in a tub. Instead, talk to Slackjaw and do what he asks. After talking to him for the final time, you'll unlock this achievement.

I would highly suggest doing this achievement during your high chaos playthough, as I stuck strictly to the main missions when doing my low chaos/ghost playthough. Avoiding all of the side missions makes the stealth playthough much easier. IF YOU ARE GOING FOR THE CLEAN HANDS ACHIEVEMENT, KILLING GRANNY RAGS OR SLACKJAW WILL NEGATE THAT ACHIEVEMENT.

If you have any further comments, questions, or feedback, please let me know via PM or comment below.

Video Credit to iGnomeoHD

! PLEASE READ: The final side mission for Slakjaw is ONLY accessible by completing his first two side missions (see below) and Granny Rag's first two side missions (see the achievement: "Gentlemen Callers" before you get to mission 7: The Flooded District, otherwise the thug you come across in the sewers in mission 7 will not be there and as such you will not be able to complete either the "Gentlemen Callers" or "Street Conspiracy" achievements.

Slakjaw has two side missions for you to complete in Mission 3: House of Pleasure, which have a bearing on your main objective in this mission as both Pendleton Twins must remain alive! Completing both side missions unlock the way to Slakjaw's final side mission in Mission 7: The Flooded District.

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SIDE MISSION 1: FIND CROWLEY

Opposite Granny Rag's house, there is a small Alley with a thug at the entrance, don't worry about him, as you run past him he will tell you Slakjaw wants to speak to you. As you go through archway, you will see two thugs outside the Dunwall Distillery (the same place as you go for Granny Rag's side mission).

Enter the Distillery, and make your way into the main building. As you enter the main room head down the stairs and you will see a door by a hanging chain. Go through the door and follow it round until you come to some stairs. By the stairs there is a small room, inside is Slakjaw. Speak with him and he will ask you to help him locate one of his men who went searching for information.

Once you have agreed to help him, head back out of the distillery, and make your way across to "Galvani's place" again (you will have already been here for Granny Rag's second side mission).

Make your way inside, and head up to the second floor. In Galvani's Laboratory, you will see two guards talking after discovering a dead body located on the table in front of them. There are two approaches to reach the body, lethal or non-lethal.

LETHAL: Simply kill the two guards (one of them has a key to unlock the way out in the same room) and take the voice recording card that is located on the table to the left hand side of the body (near it's right hand).

NON-LETHAL: When you get to the large double doors of Galvani's Laboratory, use blink to get to the end of the table nearest you, then you can crawl under the table right up to the body and the guards. When the guards stop talking, one will turn around and look at some writing on some chalk boards, the other will walk off to the right and stand near the fire.

Once the guard directly in front of you has his back turned to you stand up from under the table, take the voice recording card located to the right of the body (as you look at it) and then pickpocket the key needed to exit "Galvani's place" via the room you are currently in. Duck back under the table as the guard who walked to the fire will start walking back your way.

Once you have the key, blink to the large double doors on the left of the room, unlock it and exit the building. There will be a guard on the balcony outside, so either kill him or knock him unconscious. Then make your way back to the Dunwall Distillery to speak to Slakjaw.

Enter the Distillery, and head back to the main building, but instead of heading to where you first met Slakjaw, go through the entrance and head to your right when you see some metal stairs going down and 1-2 thugs at the top.

Slakjaw is in the room just to the right and give him the recording.

After listening to the recording, he will offer you a way to deal with the Pendleton Twins (your targets for this mission) in a non-lethal maner if you perform another task for him.

Accept the next task.


SIDE MISSION 2: ART DEALER'S SAFE

Once you have accepted the task to obtain the code to the Art Dealer's safe, head back out of the Distillery altogether.

CAUTION!: There are three assassins located in the buildings and balconies above and to the right of you.

NOTE: This is a perfect opportunity to unlock the achievement "Food Chain" which requires you to assassinate an assassin (if your going for the non-lethal approach, save your game as soon as you exit the distillery altogether and are back in the street with the thugs outside the entrance. Once you have assassinated an assassin (killing him with your blade by getting behind the assassin undetected and pressing (RT), knocking him unconscious or killing him with any other weapon won't unlock this achievement) reload your saved game and carry on with the mission).

Now you need to head to the "Golden Cat" to obtain the art dealer's code for his safe.

By accepting this side mission, Slakjaw has given you a key to an abandoned building called the "Captain's Chair Hotel" (a waypoint will appear onscreen), using this abandoned building will take you onto the rooftops just outside the Golden Cat and is by far the easiest route to take if going for a stealth playthrough.

Make you way to Captain's Chair Hotel, unlock the door and make your way up the stairs to the very top. Go out the door and you will be at the Golden Cat.

(There are many ways to infiltrate the Golden Cat, even with a lethal approach be cautious no to draw to much attention to yourself as the Pendleton twins may be alerted to your presence and come with guards to kill you which will stop you completing this side mission and thus getting the achievement.)

The easiest way to enter the Golden Cat is via the rooftops to the left hand side of the area, blink across to the gazebo roof and then blink across to the ledge on the main building and follow it round to the right and through an open window hatch.

Make your way to the objective marked art dealer and enter the room he is located in. There are no guards in the room so go in making sure you close the doors behind you as guards patrol outside the room.

Walk up to the art dealer who is blindfolded and fastened in a chair of pleasure. Use the small red lever to the right of him to electrocute him numerous times until he asks you who you are and what you want. Select the option for the safe code and the art dealer will tell you it.

Now you need to continue with the mission to rescue Emily, remember you must NOT kill the Pendleton Twins!

Once you have rescued Emily, you need to head back to the distillery to give the safe code back to Slakjaw.

NOTE: There is an achievement available here called "The art of the Steal" which requires you to rob the art dealers safe before handing the safe code over to Slakjaw. -- Robbing the safe first before giving the code to Slakjaw will NOT affect his side missions in anyway so is 100% safe to do.

After robbing the safe (or not) make your way back to Slakjaw at the distillery, and give him the safe code. He will be located in the same room he was in when you gave him the voice recording of Crowley from his first side mission.

Give him the code and he will then, tell you he will keep his end of the bargain and deal with the Pendleton twins in a non-lethal way.

There are now no more side missions for Slakjaw until Mission 7: The Flooded District so continue with the game as normal.


MISSION 7: THE FLOODED DISTRICT

Work your way through the mission as normal, when your are escaping through the sewers after taking Daud's key, you will come across a thug and opposite him are some red pipes and a small opening to your left.

Speak with the Thug and he will tell you that Slakjaw has been captured and gestures that you may be able to save him.

Make your way through the small opening above the red pipes and continue down the path to the end (you will have to swim part of the way as well as kill or bypass numerous River Krusts).

Once at the end, you will enter a large cavern with Slakjaw in shackles to the right and Granny walking around. Approach Granny, and she will ask you to help her kill Slakjaw. Refuse to help her and she will say "you'd better leave", she will then walk off. Speak to Slakjaw, and he will ask you to kill Granny Rags for him.

Agree to help him and Granny will become hostile. She will appear in random locations in the cavern. If you try to 'kill' her before having destroyed her cameo, she will turn into a swarm of rats that will come and attack you. She will then reappear somewhere else. Also if you take too long, to reach the cameo, she will spawn large swarms of rats and send them after you.

!Until her cameo has been destroyed, Granny is immortal and cannot be killed!


DESTROYING THE CAMEO:

Slakjaw tells you the only way to kill Granny is by throwing her "cameo" into the furnace. The cameo is located in the room at the highest point in the cavern, there are stairs leading up to it. Run up the stairs to the right of the cavern all the way upto the top. Once you reach the top, to the right of the room, you will see a bed, on the bed will be Granny's Cameo hidden under some cushions, pick it up and then use the lever to the left of the huge furnace to open it. Once it's open, press (X) to place the cameo in the furnace, then use the lever again to destroy it.

Now you have destroyed the cameo, Granny Rags is now mortal and can be killed easily by any means you see fit. When you have killed her, loot her for the "sewer key" and return to Slakjaw, interact with the leaver to the left of him to unlock the shackles and free him. The achievement will then unlock.

To leave, head back up to where you destroyed the cameo and there will be some wooden boards, covering up a hole. Destroy the boards with your sword and jump down into the hole to be swept off in the water.