The player assumes the role of a young Arthur, before the legendary days of Camelot. The "sword in the stone" that would signify Arthur's destiny to rule has been stolen by the evil King Lot. In the quest to regain the sword, Arthur must prove to Merlin that he has the qualities needed to be a great king: chivalry, experience, and wisdom. Merlin assists Arthur by giving him periodic advice as well as the power to transform into animals, but also tells him that unless Excalibur is recovered within three days, Lot will usurp his destiny as a king of legendary stature.

[from Wikipedia]