On a bleak Scottish moorland, Macbeth and Banquo, two of King Duncan's generals, discover three strange witches. The witches prophesy that Macbeth will be promoted twice: to Thane of Cawdor and King of Scotland. Banquo's descendants will be kings, but Banquo isn't promised any kingdom himself. The generals want to hear more, but the "weird sisters" disappear.
Soon afterwards, King Duncan names Macbeth Thane of Cawdor as a reward for his success in the recent battles. The promotion seems to support the prophecy. The King then proposes to make a brief visit that night to Macbeth's castle at Inverness. Lady Macbeth receives news from her husband about the prophecy and his new title. She vows to help him become king by whatever means are necessary.