This scene, at the start of Act 5, shows Lady Macbeth's guilt and how her conscience has finally driven her mad. This serves as an opposition to Act 1, sc. 5, when Lady Macbeth asks for the powers of darkness to fill her with cruelty and to stop her from being bothered by her conscience (Act 1, sc. 5, ll. 46-60). She appeared to be the strong one as opposed to Macbeth, at the start of the play and now she is the one who succombs to her guilty conscience while Macbeth continues to wage war with his enemies. The scene is also ironic because Lady Macbeth insists that she always have a lighted candle with her, which again, serves to contrast the powers of darkness that she summoned earlier. The scene also allows Lady Macbeth to confess her crimes. She talks as she sleepwalks and she talks about the killing of Duncan and the killing of Macduff's family. Finally, the scene sets up her death by suicide which adds to Macbeth's woes.