News of Duncan's death reaches all at the castle. Lady Macbeth faints and Macbeth kills Duncan's two guards for his murder, largely freeing him from suspicion. Duncan's two sons flee, leaving Macbeth to be crowned the new King of Scotland, his wife, the new Queen. Banquo wonders whether his friend killed the King. Fearful that his children will not be kings, the new King arranges for Banquo and Fleance to be murdered. Banquo is killed but Fleance survives. The King later sees Banquo's Ghost at his party, causing the Queen to finish their party early such is her husband's strange behavior. Hecate scolds the Three Witches for helping an ungrateful Macbeth, telling them to use illusion and prophecy against him. The King meets the Witches, learning that he should fear Macduff, that none naturally born can harm him and that he has nothing to fear until "Great Birnam wood" moves to "high Dunsinane hill" near his castle. Learning this, he decides to kill Macduff and decides he is safe from all men and that only the impossible moving of a nearby forest to his castle can spell his doom.

Unable to kill Macduff, the King has his family murdered instead... We learn that Scotland under the tyrant's rule has been plunged into despair and that a large army is gathering against him. The Queen goes insane, making her famous speech that she cannot wipe away the blood on her hands. Meanwhile, the Tyrant's enemies led by Malcolm, gather near Dunsinane. Malcolm now orders each man to cut down a branch from the nearby Birnam Wood as his army, now camouflaged, heads towards Macbeth's castle... The Tyrant laughs off his enemies' numbers, certain of the Birnam Wood prophecy, learning that his wife has died. The King, seeing Birnam Wood moving on his castle, defiantly sets off to meet his destiny... Confronted by Macduff, the King learns that he has born by Caesarian section, the hated tyrant being slain and order being restored when Malcolm is hailed the new King of Scotland...