An unnamed adventurer arrives at the entrance of a mysterious underground empire, tasked with recovering twenty hidden treasures. The protagonist must navigate a labyrinthine subterranean environment, solving complex logic puzzles and managing limited inventory space to survive. The narrative unfolds through a text-based interface where the player inputs commands to interact with the environment, facing hazards such as darkness, traps, and hostile creatures. The world operates on a rigid set of logical rules, requiring the player to map the geography and experiment with object combinations to progress through the ruins of the Great Underground Empire.

Discussion often centers on the historical significance of this title as a foundational work in the interactive fiction genre. Readers and players frequently highlight the challenging nature of the puzzles, which require careful observation and logical deduction. The atmosphere is often described as immersive despite the lack of graphical elements, relying heavily on evocative prose to build the setting. Critics note that the game established many conventions for adventure games, including the importance of mapping and resource management. The enduring appeal of the work is attributed to its clever design and the sense of discovery it provides to those who engage with its text-based world.