Macbeth and Banquo are generals commanding armies under the King of Scotland, Duncan. They are returning home after a victory over a rebel army. They meet up with three weird sisters (or witches) who tell Macbeth he will become Thane of Glamis, Thane of Cawdor and, eventually, King of Scotland. They also promise Banquo that his sons will become King. Already Thane of Glamis, when Macbeth is conferred with the title of Thane of Cawdor, the kernal of hope that he will fulfill the weird sisters' ultimate goal of King begins to grow into ambition. Once he tells his manipulative, cunning wife about the prophecy, everthing is set into motion and they begin to hatch a plot to create destiny. Good thing for them Duncan, King of Scotland is coming for a visit to further honor Macbeth.
Although confronted by conscience, Macbeth does indeed kill the King, with a little help from his wife. Malcolm and Donalbain, the king's sons, flee the country and Macbeth takes advantage of this move to cast suspicion on them. Macbeth is next in line to the throne since the King's sons are out of the country and so is crowned King, bringing the weird sisters' prophecy to completion. At least as far as Macbeth is concerned.
But Macbeth remembers that the sisters promised Banquo that his sons would one day sit on the throne. He plots to kill Banquo and Banquo's only son, Fleance. Macbeth announces a feast, inviting Banquo and Fleance above all others. On the way to the feast, Banquo and Fleance are set upon by murderers from Macbeth. Banquo is killed but Fleance escapes.
Macbeth is now near madness, overcome by ambition and fear. He goes to the weird sisters and is there warned to beware of Macduff, however he hears good news that no one who is born of woman shall ever harm him.
He is also given the strange advice to have no fear until Birnam Wood (a forest) shall come against him. He demands to know if Banquo's son will still become King and learns that it is destined still. After leaving the sisters, Macbeth learns that Macduff has escaped to England to join up Malcolm. Nearing the edge of insanity, Macbeth responds by killing Lady Macduff and her children.
Lady Macbeth has crossed over the edge of insanity. She walks in her sleep and tries to wash imaginary bloodstains off her hands. Macbeth is fighting with few forces and is terrified to learn Birnam Wood actually seems to be moving toward him. Actually, the moving forest is really just branches cut off and carried by soldiers as camouflage. But Macbeth hearkens back to the news that none of woman born can harm him and fights with renewed strength and spirit. He begins fighting against Macduff and then remembers that the sisters also warned him against this man. Thinking he leads a charmed life, he cries out that he cannot be killed except by one not born of woman. Then he learns that Macduff was ripped out of his mother's womb, born by the C-section of the times. Macbeth is killed and Malcolm is named King of Scotland.