The events of the game are set in a fictional version of Britain in the 5th century. The evil sorceress Morgana has magically imprisoned King Arthur and the Knights of the Round Table in the Cave of Glass beneath her castle, past Hadrian’s Wall. At Camelot, the King’s wizard Merlin uses a crystal ball and locates a brave team of “warriors” in the future, led by Arthur King and dubbed “The Knights”. They are actually American football players, though Merlin interprets their names as a sign of fate. He summons them back in time, and the Lady of the Table transforms them into “Knights of Justice”.
Merlin asks them to break the seal on King Arthur and the Knights of the Round by gathering the twelve Keys of Truth. The party retrieves the Excalibur sword from the Lady of the Lake, proving their worth by claiming the Pendragon Shield from a young dragon at Shield Heights. They assist Erek, the deposed ruler of Tintagel Castle, and recover the first Key of Truth in the castle. They make their way into the village of Welton, which is under a mind control spell, and recover the second Key of Truth at Gruesome Keep. After breaking the spell on Welton and crossing the Blinder’s Way, they claim the third Key of Truth at Castle Sanguine.
The game is an action-adventure game, played from a top-down perspective. The player takes on the role of Arthur King and is accompanied by two Knights of Justice controlled by the game console. The player battles enemies using a regular sword swing or a special attack, and can block high and low attacks. Twelve Knights are available from the start (including Arthur King), each with his own weapon, personality and statistics for life force, defense, strength and speed. Each boss of the game has a specific weakness against one of the Knights.
Changing party members is done by visiting the Round Table room in Camelot. Each character has a life meter, and Arthur also has a power meter. Various items must be collected to complete quests and objectives, while some can be used to restore a character’s life meter. An overworld map feature allows the player to directly access locations already visited once. The game has no saving feature but allows accessing various points of the storyline with a system of passwords.