You have reached Basso and the old chapel. This walkthrough contains steps to help you get in the foundry, steal the ring from the General, and escape the foundry.
In Thief, players have many ways to complete a mission. However, this tutorial focuses on the stealth path which allows you to play through a level without killing too many enemies.
You have seen the Queen of the Beggars in the Lockdown chapter. Now, we need to get into the Foundry.
1. Because there are many guards and light areas, my advice is to avoid fighting as much as possible, or you will lose your health and armor unnecessarily.
To get down safely, grab the rope, go down, and press X to land on the crate.
Next, climb up the ladder on the opposite side. This area is completely dark, so the guard on the bridge will not be able to spot you.
Get to the other side of the area by taking advantage of the shadow. Once you reach that side, jump into the hole, which lets you get closer to the gate safely.
You should be very close to the gate when you get out of the hole. As one of the guards is heading to the other side of the area, turn right, and pick the lock on the gate.
Open the gate, and get to the other side of the wall to get to the foundry.
2. This area is rather safe, so you can move quickly without being spotted. Follow the white spot onscreen, and climb up the pipe to get inside the foundry.
When you see a guard below you, take him down as soon as possible, or you will not be able to jump down.
After you take down the guy, go downstairs, and look out of the window to trigger the next objective.
To get through the three guys in the area without being noticed, jump out of the window to the anchor, and jump to the left twice to get to the second floor.
There will be a guard on this floor. However, as he is walking, you can sneak behind him without being spotted. Wait for the right moment, follow him, and then turn right.
After getting past the guard, jump onto the crate, and grab the hook to go deeper into the factory.
3. As soon as you get to the next factory area, jump to the ground, or the guard will spot you.
Go to the corner of this room, and pick the lock on the door to get to the next area. Proceed with caution. There is broken glass on the ground, so you should try to walk slowly to avoid making unnecessary noise.
Be careful in the next area because there will be a guard near the unlocked door. However, he quickly follows another guy. The safest way to go deeper inside the factory is by following this guard. However, before you do that, make sure you have a bottle because you will use one later. If you do not have a bottle, grab one in a nearby room. (The room is marked with a red arrow in the picture.)
At some point, the two guys will stop and block your way. To cause a distraction, throw the bottle to the side that is opposite the guards, and then quickly hide in the cabinet. As the two guards come to see what happened, get out, and quickly get to the next room on the left.
4. Now that you are in deeper, you will see a guard sleeping. There is a locked door on the left side which requires a special key to unlock. The key is in the wardrobe in front of the guard; you will have to pick the lock the on wardrobe to get it.
Next, jump to higher ground, and grab the hook again.
5. In the next area, jump to the ground as soon as you hear someone talking so that you will not be spotted, and walk along the route to get the lower floor of the building.
After the cutscene, your objective is to get the ring from the General. In order to get to his room, go to higher ground, and take advantage of the shadow to get through the guards. There is a small hole in the window that lets you see where the General is putting the ring.
After you see him put the ring in the strong box, turn back, and climb into the hole on the left side to get into his room.
Now that you have access to the strong box, you will have to solve a puzzle to unlock it. Use the arrow keys to switch and rotate the squares to make the center of the board a circle to unlock the box.
6. After you get the ring, a guard spots you, and rings the alarm. You have to get out of there using the back door as quickly as possible. There will be two guards outside. Move quickly to the opposite side while they are talking, or you will be spotted later.
Wait for the two to separate, and head to the alley in front of you.
Go behind the other guard in this area to get to the white spot. Even though you can use the water arrows to extinguish the flames, you should not. Instead, jump in the hole, and get to the other side of the room. Now, no one can see you because they are focusing on the other side.
As one guy leaves the area, you should be able to jump to the other side without any trouble. From there, you can follow the blue-highlighted path to get out.
7. Once you get out, there will be three guards actively seeking you, so it would be very dangerous to fight all of them. To get through this area, you first jump on the soft rooftop. The broken rooftop will cause noise and draw the attention of the guards. One of them will go check what has happened from the window. At this point, you have to get out of the house quickly, turn right, and crawl under the crate. If you do not perform this action fast enough, you will fail.
Next, quickly get into the house using your special ability. There is a guard in this area, so keep an eye on him.
8. Once you are in the house, get to the top floor, and escape using the window.
We will need to meet Basso in our next step to complete the Dust to Dust chapter next.