IMPORTANT: If you are playing the PC or Macintosh version, SAVE YOUR GAME HERE AND DO NOT OVERWRITE THIS SAVE UNTIL YOU HAVE OBTAINED SECRET #6! There is a potential bug in this area, in which saving and reloading may result in invisible walls blocking the passageway into the large room and/or the smaller room with the sixth secret. This short video walkthrough covers the same sequence shown in the screenshots below. As far as I know, this bug does not affect the PlayStation version.

Jump into the water beyond the ledge where you found the 2 bundles of harpoons. Swim to the right along the brick passage.

You'll pass a small, wooden door on the right wall and a trapdoor in the ceiling on the left.

At the end of the passageway, swim around the corner to the right, into to a room with a glass ceiling where you can surface for air. (You can also see another UPV and some goodies in an adjacent room. This is SECRET #6. You'll get to it soon.)

Pull the underwater lever to open the trapdoor you passed a moment ago.

Swim back around the corner and climb up through the trapdoor.

When you pull up onto the ledge near the window...

...the camera shifts to show a guard and frogman in the next room. Do not fire weapons here, or you'll attract their attention. An alarm will sound and a door will close, preventing you from getting secret #6. You will then have to reload and try again if you want the secret.

NOTE: There are some general notes and a diagram for this area in the main walkthrough.

Press the button near the window to open the other small door in the underwater passage. (You passed it on your way here.) Drop into the water...

...and swim through the door you just opened.

If you save and reload after using the lever and button but before swimming into the big room, you may run into an invisible wall in the connecting passageway. If this happens, reload your earlier save and try again.

When you exit the tunnel, stay close to the bottom...

...as you swim to the far right corner of the room.

This area has a wooden floor and 2 small openings below the waterline.

You can surface here and not be seen by the guard above. Again, it doesn't matter if you're in the frogman's line of sight, since he will not react and trigger the alarm. Even though it's safe here, don't save or you'll risk triggering the invisible wall bug.

[Part 2 | Return to the Lud's Gate Walkthrough]