Three witches meet Macbeth and Banquo and make predictions about each of their futures. Ross and Angus arrive from the king to confirm the first of the predictions, that Macbeth is the new Thane of Cawdor. Macbeth contemplates what he should do to make the other predictions come true.
Macbeth's wife (Lady Macbeth) receives a letter from her husband describing his meeting with the witches and their predictions. He also says the king is coming to visit. Lady Macbeth call on spirits to fill her with cruelty so that she can be the strength Macbeth needs to kill the king. She assures Macbeth that she will take care of all the preparations for duncan's visit
Macbeth returns to Lady Macbeth in their bedroom, bloody daggers in hand, after he has killed the king. He is horrified at his own actions. Lady Macbeth returns the daggers to the murder scene and urges Macbeth to wash his hands and recover his wits.
Drunk gatekeepers go talk to the king, they find him dead. Macbeth kills the guards, who appear to be guilty of the murder. Duncan's sons, Malcolm and Donalbain flee to safety in England and Ireland, to avoid being murdered or accused of murder.
Lady Macbeth expresses her unhappiness. Both she and Macbeth are suffering from troubled sleep, nightmares and loss of appetite. They are determined to hide their agitation and to welcoming and jovial at the banquet. Macbeth hints to Lady Macbeth that he has made plans for some significant action, but refuses to give her any details.
Banquo’s ghost enters and sits at the table. The guests, who do not see the ghost, are startled by Macbeth’s horrified reaction. When the ghost disappears, they blame his poor behaviour on poor health. Then the ghost appears again and Lady Macbeth asks the guests to leave.