The player again arrives into the city of RHEM, with a note from Zetais who studied the artifact in RHEM 2: The Cave. Kales uses the note given by the player to unlock a gate leading to the inner area of RHEM. The game's overall plot is not fully revealed until the player comes back to this area after solving a large number of puzzles.
As stated in the game's title, in order to solve most of the major puzzles, the player must first find and enter a "hidden library", a jumble of rooms containing roll doors and books on shelves. The books themselves contain hints to solve the other puzzles.
The player's goal is to find 10 green crystals scattered throughout RHEM, much like the other two games, in order to unlock the passage to a black crystal.
RHEM 3: The Secret Library System Requirements
Processor: Intel Pentium III / AMD Athlon MP
Graphics: AMD Radeon Xpress 1200 Series or NVIDIA GeForce 6200 LE
PC System Analysis For RHEM 3: The Secret Library Requirements
Your PC will need a graphics card thats as powerful as a GeForce 6200 LE/Radeon Xpress 1200 Series and it should be paired with either a Athlon MP/Pentium III CPU to match the RHEM 3: The Secret Library recommended system specs. This PC setup will deliver 60 Frames Per Second on High graphics settings on 1080p monitor resolution. Also your PC needs 256 MB RAM to meet the rec specs and run at 60 frames. Make sure your GPU can run DirectX 9 or RHEM 3: The Secret Library won’t run.