Amnesia: The Dark Descent Walkthrough: Cistern

Good job on getting out of the Prison! That’s another area where a lot of
people have given up on due to fear, but since you got out of it, you can
feel quite accomplished!

As soon as you enter the Cistern, you’ll have a flashback of Daniel talking
to Alexander about how the sewers are being used as a means of transport.
Alexander also talks about how there are sometimes poisonous fungi at
times, but there’s also a vaccine.

When the flashback is over, it’s time to explore the place. In front of us
is a structure supporting a bridge above us. There are two more bridges
hanging in the air. Move forward and when you’re near the center, look
to the right. There’s a pipe spewing out oil. It’s an “Oil Drainage”.
Open your inventory and use the Glass Jar on it. It will be placed on
the ground and you can pick it up and have a Glass Jar of Oil

Continue into the hall where the “Oil Drainage” pipe is and go down the
stairs. Walk into the water and you’ll find out that you can’t continue.
You have to drain the water somehow.

Go back into the main Cistern room. Move around the structure at the
center and you’ll find a lever and a ladder. Pull the lever. It will need
to be greased first since it’s stuck. Open your inventory and use the
Glass Jar of Oil on it. After it’s been oiled up, pull the lever again.
The pipe is blocking the ladder from fully going down.

Now we will make the ladder destroy the pipe! Instead of pulling down on
the lever, pull up. This will make the ladder go higher. When it’s high
up there, pull down on the lever. It’s working! The pipe is bending! Try
it one more time! Good job, now the ladder is working!

Click on the ladder to get on it and move up to climb. Once you’re at
the top, move forward. Don’t go through the door yet. To the door’s left
and right are two levers. Pull them both. The one on the right will bring
the bridge down, while the one on the left is not working.

Anyway, we won’t be going into the Control Room yet. Turn around and move
forward. We’re gonna cross the bridge on the left. Enter the door to the
Cistern.