A doctor and a gentlewoman discuss Lady Macbeth. Ever since Macbeth went to war, the gentlewoman has seen Lady Macbeth sleepwalking through the hallways of the castle but the doctor has seen no evidence of this. The gentlewoman has heard Lady Macbeth say something dreadful but she will not reveal what. As the doctor presses her for information, Lady Macbeth enters holding a candle. Lady Macbeth is sleepwalking and rubbing her hands, as though she is trying to wash them. While rubbing her hands, Lady Macbeth complains that she cannot remove a “damned spot” (5.1.25) from her skin. Continuing to talk, she bemoans the murders of Banquo and Lady Macduff and then exits. The doctor blames her behavior on supernatural forces and asks the gentlewoman to look after Lady Macbeth.

Scottish lords gather to talk about the war waged by Macbeth. They know that a large English army is approaching led by Malcolm. A Scottish army is set to join forces with them near a forest called Birnam Wood. The lords have lost faith in Macbeth, who has become a despot. Macbeth has holed up in Dunsinane Castle, where he prepares for his war while descending into madness.