Banquo and Fleance meet Macbeth in the night where Banquo speaks of the dream he saw the previous night of those three witches. Macbeth pretends that he has not thought of them.
Macbeth has this vision of a floating dagger which makes him draw out his own dagger and reinforces his evil thoughts regarding the murder of Duncan amidst the horror of the night such as witchcraft and wicked dreams.
Lady Macbeth speaks of her strength. She couldn’t kill the king because in sleep he resembled her father. Macbeth comes after murdering the king and both assure each other. Macbeth is haunted by his conscience which he says won’t let him sleep peacefully anymore.
Lady Macbeth accuses him of weakness in purpose. She asks him to wash his hands and doing so should wash off the guilty conscience from him. Together they decide to pretend as watchers when the news of the murder arrives at them.
In Macbeth’s castle, a porter hears knocking and fantasises himself as a porter at the gate of hell answering to Beelzebub. Finally, he responds and Macduff and Lennox enter and inquire of his late response to which he says that he was wondering of the effects of drinking alcohol and compares it to the paradoxical effects of lechery.
Macbeth comes and leads them towards the king’s chamber where Macduff returns with a cry of horror. Everyone arrives at the scene and due to the seeming evidences, Lennox presumes of the King’s chambermaids as murderers.
Lady Macbeth starts acting in the most affecting manner. Macbeth and the rest decide to meet in the hall. Malcolm and Donalbain decide to leave for England and Ireland respectively.
Outside Macbeth’s castle, Ross and an Old Man ponder upon the nature of evil happenings in the preceding days. Macduff enters the scene and informs them of Macbeth’s ascension to the throne. They suspect both princes too for leaving the site. Macduff leaves for Fife and the other two leave for Scone to witness the coronation of Macbeth, the new king.