>>96362708
The setting/premise of PSO is:

Your homeworld has been wrung dry of resources and your people are desperately searching for a new one to migrate to. They find a lush jungle planet with unmanned probes and proceed to set up a massive exodus on colony ships. The first ship is Pioneer 1, which goes to the new world and starts setting up infrastructure, government, mines, etc. Once they're established, they send the second, larger ship, Pioneer 2, on which the players arrive. As you make contact with the surface city, an unnatural cataclysmic explosion kills everyone on the surface. You are now stranded between a now known to be dangerous planet and an impossible return journey with a dying planet on the other side anyways. Find out what happened to Pioneer 1 by exploring what's left of the city and what they disturbed far underground. Eldritch things meant to be left buried for all time may be involved.