On a Scottish battlefield three witches gather to meet with the victorious general Macbeth. They tell him he will soon be Thane of Cawdor and later king and promise his comrade Banquo that his heirs will be kings. News arrives from King Duncan that Macbeth is now indeed Thane of Cawdor as a reward for his loyalty. Duncan tells Macbeth he will stay at his castle tonight.
Lady Macbeth reads a letter from Macbeth about his meeting with the witches. Macbeth arrives home and she persuades him they must kill the king while he is in their castle to make the prophecy come true. With Duncan under his roof as his guest, Macbeth has second thoughts, but Lady Macbeth forces him back to the plan.
Macbeth kills Duncan in the night, but the crime horrifies him. Lady Macbeth must complete the job and place the bloody daggers with the king’s sleeping servants so that they are blamed for the deed. A knocking on the castle gate rouses the drunken Porter who fantasises about being a porter at the gates of hell before letting in Macduff and some other nobles. The murder is discovered and Macbeth himself kills the kings’ servants in an apparent fit of righteous anger. The king’s sons, Malcolm and Donalbain, are suspicious and flee to England and Ireland for their own safety. They are now blamed for their father’s murder and Macbeth is crowned King.
Macbeth arranges for Banquo and his son Fleance to be murdered, but only Banquo is killed and the boy escapes. At a banquet Banquo’s ghost appears to torment Macbeth’s conscience. Macbeth is suspicious as to why Macduff did not attend the banquet and decides to meet again with the witches.
The witches and their Queen Hecate present several apparitions to Macbeth which convince him of his invincibility, but a final vision confirms that Banquo’s heirs will be kings. Hearing that Macduff has gone to England, Macbeth orders the slaughter of his wife, children and servants.
In England Macduff tries to persuade Malcolm to fight for the Scottish throne, but Malcom is suspicious and lies about his own vices to gauge the truth of Macduff’s intentions. Satisfied that Macduff is honest, Malcolm agrees to attack Macbeth with the support of the English king. When news arrives of the murder of Macduff’s family, the desire to overthrow the tyrant Macbeth becomes even stronger.
Back in Scotland, Lady Macbeth is tormented by sleep-walking nightmares. Besieged in the royal castle, Macbeth comforts himself with the witches’ prophecies, despite the desertion of most of his supporters and at last the suicide of Lady Macbeth. The prophecies themselves begin to crumble and finally Macbeth is left facing Macduff in combat. The witches promised him he could not be killed by any man of woman born, but Macduff tells him he was born by Caesarean section. Macbeth realises his time has come, but resolves to die fighting. Macduff kills Macbeth and proclaims Malcolm the new king of Scotland.