"Ruins" is a solitaire adventure, intended for a single player with no need for a game master. In it, the player takes the role of Jedi Knight Keval Raffaan, who has been sent to the planet Muzara to mediate a dispute between the native Muza species and a group of Human settlers from the Brentaal League who are fighting over land-use rights. In order to prove himself worthy to settle the conflict, the Muza clan elders insist that Raffaan must first undertake a test of his mettle: he must venture into the ruins of Kabus-Dabeh—a site the Muza consider evil—and recover a leather sack filled with coins. Raffaan accepts.
The scenario allows the player to choose various actions from a small list of possibilities. At certain locations, the player must roll dice to see whether these actions succeed or fail. The "correct" path leads Raffaan down a dry well, through a subterranean cavern, and back out with the sack. He then negotiates a truce between the Muza and the Human settlers. Other "incorrect" paths lead him into a dark cave, where he confronts an intelligent monster called Togarn, into a dark pond, which stains the Jedi's arm gray, and up a pyramidal structure, where he must escape an ancient trap.