The Dark Crystal is closely based on Jim Henson's film of the same name. The game is set in Thra, a world with three suns, which come together every thousand years in an event known as "The Great Conjunction". The player controls Jen, the last survivor of the Gelfings, a race of mole-like people. He must find a dark crystal and its broken shard, and repair it to end the reign of a tyrannical lord.
Like other installments of the Hi-Res Adventures series, the game is entirely text-based, with non-animated graphics to illustrate the areas. Movement between areas and interaction with the game world is performed by typing commands consisting of either one or two words (a combination of a verb and an object).