You take the part of Shelby, apprentice to two Regulators whose job it is to take care of a beacon. The beacon ensures the world's continuing existance.
But when you return from a trip, you notice that the beacon has gone dark and that the Regulators are nowhere to be found.
Notes
The game is listed as the third in the Quest Adventure series which started with Colm's game Manor of Madness on the ZX Spectrum.