Faith is with the lesbian cannibals and lost her memory. Larry has to find the Cavern of Cosmic Cognition and get Faith there. The key to the cavern are the four keystones.
Unlike normal walkthroughs, in Nice Game Hints you can select just the puzzle you want hints for. Here are listed the puzzles for "The Cavern of Cosmic Cognition" in Leisure Suit Larry - Wet Dreams Dry Twice. The guide you choose only contains information about that puzzle, reducing possible spoilers for other puzzles.