"The thane of Fife had a wife. Where is she now?- What, will these hands ne'er be clean?-No more o'that my lord, no more o'that. You mar all with this starting."
"Go to, go to. You have known what you should not."
"Or so much as it needs, to dew the sovereign flower and drown the weeds. Make we our march towards Birnam."
"What soldiers, whey-face?"
"The English force, so please you."
At night, in the King's palace at Dunsinane, a doctor and a gentlewoman discuss Lady Macbeth's strange habit of sleepwalking. Lady Macbeth enters in a trance with a candle. She seems to see blood on her hands and claims that nothing will wash it off.
Outside the castle, a group of Scottish lords discuss the military situation. The English army approaches, led by Malcolm, and the Scottish army will meet them near Birnam Wood to join forces with them. Macbeth has fortified Dunsinane Castle and makes preparations in rage.
Macbeth enters the hall of Dunsinane with the doctor and his attendants, boasting that he has nothing to fear from the army or Malcolm since "none of woman born" can harm him. He calls his servant, Seyton, who says that an army of 10,000 Englishmen are approaching the castle. Macbeth insists on wearing his armour, thought the battle is still some time away. The doctor tells Macbeth that his wife is kept from rest due to her delusions and Macbeth orders him to cure her.
"So, thanks to all at once and to each one, whole we invite to see us crowned at Scone."
Near Birnam Wood, Malcolm talks with the English lord Siward and his officers about Macbeth's plan to defend the castle. They decide that each soldier should cut down a bough of the forest and carry it in front of him as they march to the castle, disguising their numbers.
"Let every soldier hew him down a bough and bear't before him. Thereby shall we shadow the numbers of our host and make discovery err in report of us."
Outside the castle, the battle commences. Malcolm orders the English soldiers to draw their swords. On the battlefield, Macbeth strikes those around him vigorously because "no man born of woman" can harm him and he slays Lord Siward's son.
Macbeth finally encounters Macduff. They fight and Macduff tells him that he was "not of woman born" as he was delivered by c-section. Macbeth suddenly fears for his life, but says that he won't surrender. Malcolm and Siward walk together into the castle. Siward is informed of his son's death. Macduff enters with Macbeth's head and proclaims Malcolm King.
"Hail king! For so thou art. Behold where stands the usurper's cursèd head. The time is free. I see thee compassed with thy kingdom's pearl, that speak my salutation in their minds, whose voices I desire aloud with mine. Hail, King of Scotland!"