Turn left, follow the walkway, enter the door and turn left. Jump down into the water, swim to the secret room packed with goodies, and swim out to find a lever. Push it, surface, and take either passage from the lower walkway.

Swim under the pools to a connecting passage, and another that leads to another lever. Push it, surface and head down the passage that leads to a landing with two Slith guarding a stinger. Head to another pool and passage that leads to a gold door - open it and go in to find a crucified Nali. Head up to the ramp to the main room. Kill all the Skaarj and the stone blocking the doorway at the top of the ramp will open.

Carry on through to another lever, which will activate a lift - take it, follow the walkway, jump into the water at the end and swim to the next platform, with a Nali Priest. Dive in the water again, swim to another platform, kill the Slith and push the lever to fire the grappling hook. Jump onto the gun, walk up the cable to the small niche, go up the next board and drop to the narrow bridge below to get some eightballs.