Banquo and his son Fleance walk in the torch-lit hall of Macbeth’s castle. Fleance says that it is after midnight, and his father responds that although he is tired, he wishes to stay awake because his sleep has lately inspired “cursed thoughts” (II.i.8). Macbeth enters, and Banquo is surprised to see him still up. Banquo says that the king is asleep and mentions that he had a dream about the “three weird sisters.” When Banquo suggests that the witches have revealed “some truth” to Macbeth, Macbeth claims that he has not thought of them at all since their encounter in the woods (II.i.19–20). He and Banquo agree to discuss the witches’ prophecies at a later time.

Banquo and Fleance leave, and suddenly, in the darkened hall, Macbeth has a vision of a dagger floating in the air before him, its handle pointing toward his hand and its tip aiming him toward Duncan. Macbeth tries to grasp the weapon and fails. He wonders whether what he sees is real or a “dagger of the mind, a false creation / Proceeding from the heat-oppressed brain” (II.i.38–39). Continuing to gaze upon the dagger, he thinks he sees blood on the blade, then abruptly decides that the vision is just a manifestation of his unease over killing Duncan. The night around him seems thick with horror and witchcraft, but Macbeth stiffens and resolves to do his bloody work. A bell tolls—Lady Macbeth’s signal that the chamberlains are asleep—and Macbeth strides toward Duncan’s chamber.

As Macbeth leaves the hall, Lady Macbeth enters, remarking on her boldness. She imagines that Macbeth is killing the king even as she speaks. Hearing Macbeth cry out, she worries that the chamberlains have awakened. She says that she cannot understand how Macbeth could fail—she had prepared the daggers for the chamberlains herself. She asserts that she would have killed the king herself then and there, “[h]ad he not resembled / [her] father as he slept” (II.ii.12–13). Macbeth emerges, his hands covered in blood, and says that the deed is done. Badly shaken, he remarks that he heard the chamberlains awake and say their prayers before going back to sleep. When they said “amen,” he tried to say it with them but found that the word stuck in his throat. He adds that as he killed the king, he thought he heard a voice cry out: “Sleep no more, / Macbeth does murder sleep” (II.ii.33–34).

Lady Macbeth at first tries to steady her husband, but she becomes angry when she notices that he has forgotten to leave the daggers with the sleeping chamberlains so as to frame them for Duncan’s murder. He refuses to go back into the room, so she takes the daggers into the room herself, saying that she would be ashamed to be as cowardly as Macbeth. As she leaves, Macbeth hears a mysterious knocking. The portentous sound frightens him, and he asks desperately, “Will all great Neptune’s ocean wash this blood / Clean from my hand?” (II.ii.58–59). As Lady Macbeth reenters the hall, the knocking comes again, and then a third time. She leads her husband back to the bedchamber, where he can wash off the blood. “A little water clears us of this deed,” she tells him. “How easy it is then!” (II.ii.65–66).

Banquo’s knowledge of the witches’ prophecy makes him both a potential ally and a potential threat to Macbeth’s plotting. For now, Macbeth seems distrustful of Banquo and pretends to have hardly thought of the witches, but Macbeth’s desire to discuss the prophecies at some future time suggests that he may have some sort of conspiratorial plans in mind. The appearance of Fleance, Banquo’s son, serves as a reminder of the witches’ prediction that Banquo’s children will sit on the throne of Scotland. We realize that if Macbeth succeeds in the murder of Duncan, he will be driven to still more violence before his crown is secure, and Fleance will be in immediate and mortal danger.

Act II is singularly concerned with the murder of Duncan. But Shakespeare here relies on a technique that he uses throughout Macbeth to help sustain the play’s incredibly rapid tempo of development: elision. We see the scenes leading up to the murder and the scenes immediately following it, but the deed itself does not appear onstage. Duncan’s bedchamber becomes a sort of hidden sanctum into which the characters disappear and from which they emerge powerfully changed. This technique of not allowing us to see the actual murder, which persists throughout Macbeth, may have been borrowed from the classical Greek tragedies of Aeschylus and Sophocles. In these plays, violent acts abound but are kept offstage, made to seem more terrible by the power of suggestion. The effect on Lady Macbeth of her trip into Duncan’s bedroom is particularly striking. She claims that she would have killed Duncan herself except that he resembled her father sleeping. This is the first time Lady Macbeth shows herself to be at all vulnerable. Her comparison of Duncan to her father suggests that despite her desire for power and her harsh chastisement of Macbeth, she sees her king as an authority figure to whom she must be loyal.

Macbeth’s trepidation about the murder is echoed by several portentous sounds and visions, the famous hallucinatory dagger being the most striking. The dagger is the first in a series of guilt-inspired hallucinations that Macbeth and his wife experience. The murder is also marked by the ringing of the bell and the knocking at the gate, both of which have fascinated audiences. The knocking occurs four times with a sort of ritualistic regularity. It conveys the heavy sense of the inevitable, as if the gates must eventually open to admit doom. The knocking seems particularly ironic after we realize that Macduff, who kills Macbeth at the end of the play, is its source. Macbeth’s eventual death does indeed stand embodied at the gate.

The motif of blood, established in the accounts of Macbeth’s and Banquo’s battlefield exploits, recurs here in Macbeth’s anguished sense that there is blood on his hands that cannot be washed clean. For now, Lady Macbeth remains the voice of calculating reason, as she tells him that the blood can be washed away with a little water. But, as Lady Macbeth eventually realizes, the guilt that the blood symbolizes needs more than water to be cleansed away. Her hallucinations later in the play, in which she washes her hands obsessively, lend irony to her insistence here that “[a] little water clears us of this deed” (II.ii.65).