When the drunken porter of Macbeth's castle finally responds to the noise, he opens the door to Macduff, a loyal follower of the king, who has been asked to awake Duncan in preparation for the return journey. Macbeth indicates the location of the king's room, and Macduff discovers the body. When the murder is revealed, Macbeth swiftly kills the prime witnesses, the sleepy guards of the king's bedchamber, and Lady Macbeth faints. The assembled lords of Scotland, including Macbeth, swear to avenge the murder. With suspicion heavy in the air, the king's two sons flee the country: Donalbain to Ireland and Malcolm to raise an army in England.
Macbeth is duly proclaimed the new king of Scotland, but recalling the Witches' second prophecy, he arranges the murder of his fellow soldier Banquo and his son Fleance, both of whom represent a threat to his kingship according to the Witches' prophecy. The hired murderers kill Banquo but mistakenly allow Fleance to escape. At a celebratory banquet that night, Macbeth is thrown into a state of horror when the ghost of the murdered Banquo appears at the dining table. Again, his wife tries to strengthen Macbeth, but the strain is clearly beginning to show.
The following day, Macbeth returns to the same Witches who initially foretold his destiny. This time, the Witches not only confirm that the sons of Banquo will rule in Scotland, but they also add a new prophecy: Macbeth will be invincible in battle until the time when the forest of Birnam moves towards his stronghold at Dunsinane and until he meets an enemy "not born of woman." Dismissing both of these predictions as nonsense, Macbeth prepares for invasion.
