St. Francis' Folly - Neptune Key
The NEPTUNE DOOR is on the top level, south wall. The switch to open it is down on the second level. If you followed the main walkthrough, it will be open now. Make your way over to it and go inside.
Jump in the pool and swim downwards...
...as the strong current carries you that way. When you reach the bottom, swim forward.
There's a gate ahead, and the key is behind it, but don't go there yet. Instead, look for an opening above on the left.
In this alcove is a lever. Pull it to open the gate and shut off the current. If you have plenty of air, roll and swim away from the lever...
...then down and to the left.
Swim through the open gate and grab the NEPTUNE KEY.
Roll...
...and swim forward. When you reach the grate in the floor, swim up the long tunnel...
...to the surface. (If you're low on air after pulling the lever, it's OK to return to the surface. Then dive down again, swim forward to get the key, and return to the top.) If you break the surface just as Lara runs out of air, you'll unlock the "So Salacia" achievement/trophy, but you can also do this easily after getting the key, as described in the main walkthrough.
DARK MODE: Even with brightness adjusted, dark images on a light background can be hard to see. May I suggest a reputable dark mode browser extension, such as Dark Reader? (Download only from trusted sites, like darkreader.org or your browser's web store.)
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