In the game, Sir Pendragon is tasked with searching a castle for the ancient Staff of Karnath, which he must destroy prior to midnight, before it wipes out the human race.

As Sir Arthur Pendragon, the player's main objective is to collect 16 pieces of a key before midnight, which when all connected will form the shape of a pentacle.

[1] The pieces of the pentacle are guarded by various magical creatures, some of which can be defeated by casting spells, others requiring accurately timed attacks and nimble dodging.

[1][3] If the player is hit by an attack of any enemy in the castle, Pendragon will lose energy, or in some cases, time will be deducted from the countdown timer.

Centuries later, an aristocrat adventurer, Sir Arthur Pendragon, ventures inside the castle in order to defuse the orb before midnight.

[5] The Pendragon series and The Staff of Karnath were created by brothers Dave and Robert "Bob" Thomas, rather than Ultimate founders Tim and Chris Stamper.

Although he later began working for the company in producing video games, he quit due to the strain of his daily 68 miles (109 km) commute.

Bob was a trained technical illustrator for the Ministry of Defence and had experience with designing interiors for the Royal Navy, which later aided to the military-themed visuals of the Pendragon series.

According to Dave, the visuals and setting of the castle were inspired by the 1962 film Jack the Giant Killer, while the plot was influenced by H. P. Lovecraft's work.

[4] The Thomas brothers decided to show their progress on the game to Tim and Chris Stamper for evaluation, despite feeling embarrassed due to their workspace being inside their parents' attic.

[6] Anderson of Personal Computer Games praised the overall presentation, asserting that the rooms were of "extremely realistic" quality.