7 Days a Skeptic is the very good 2004 sequel to 5 Days a Stranger. Like its predecessor, this is one of my favorite AGS and adventure games. Definitely worth a try.
Many centuries have passed since the DeFoe Manor incident. It is now no more than folklore and forgotten stories. The human race is going "where no man has gone before", and the invention of warp technology is fast-pacing the spaceship program. Due to vehicle shortages, the Earth Federation instigates a new program that upgrades old and retired spacecraft. The Mephistopheles is the first to undergo this program. Crewed by a new complement of six crewmen, the Mephistopheles is assigned to map out the Caracus galaxy. A few days into the voyage, the crew sight a metal locker with the name DeFoe on it. They open it to find nothing in it - or so they think...
Note: This game is gorier than 5 Days a Stranger, so I would not recommend this game to anyone who had a problem with the violence in its predecessor.