Macbeth traces the destructive elements at play when Macbeth, a decorated and respected soldier, takes matters into his own hands and, with his wife, Lady Macbeth's, persuasion, intends to ensure his position as king of Scotland, as foretold by the witches, by removing all obstacles in his way, starting with the king, Duncan, himself.
1. The witches tell Macbeth he will be king and Banquo that his sons will be kings in Act I, scene iii and Macbeth immediately considers his options in safeguarding his future, to the point that, what he is thinking is so heinous that it "doth unfix my hair," (135).
2. In Act I, scene v, Lady Macbeth expresses her intentions in persuading Macbeth. She will go to any length on Macbeth's behalf, and even begs to be filled with "direst cruelty," (40), to ensure that, if Macbeth loses his nerve she retains her resolve. She is worried that he is too weak being, "full of the milk of human kindness." (14)
3. Macbeth has resolved to murder Duncan, despite questioning his own motives and being disturbed by the vision of the daggers in Act II, scene i. The next crucial part is Act II, scene ii. Duncan is dead and Lady Macbeth has had to return the daggers to his chamber due to Macbeth's confusion.
4. Act III, scene ii is crucial in recognizing the change in Macbeth as he stops relying on Lady Macbeth. He plans to have Banquo murdered because he is concerned about the witches' prophesy that Banquo's sons could be kings. Line 45 confirms how proud of himself he is that he has put in motion his latest scheme, telling Lady Macbeth to, "Be innocent ...till thou applaud the deed"
5. In scene iv of Act III, Macbeth sees Banquo's ghost and is in a frenzy because Fleance, Banquo's son, is alive. This is important as it drives the plot and contributes to Macbeth's increasing paranoia.
6. Macbeth goes to the witches in Act IV, scene i and demands more from them. he is now more confident than ever because the apparitions tell him that "none of woman born shall harm Macbeth," (80) and that he can rest easy until "Great Birnam wood...come against him," (92). The fact that he then sees eight kings that look like Banquo is minimized in Macbeth's eyes as he now knows h is invincible.
7. The killing spree continues and meanwhile MacDuff and Malcolm conspire to return to Scotland and defeat Macbeth. In Act V, scene i Lady Macbeth makes an appearance and her condition has seriously deteriorated. She is obsessed with removing the "damned spot," (34) which apparently plagues her and her doctor can do nothing more for her. As he says, "more needs she the divine than the physician," (72).
8. Macbeth is saddened by her death in Act V, scene v and is beginning to see the futility but not sufficiently enough to make him surrender. Even on realizing that the witches are nothing more than "juggling fiends," in the final scene (scene viii) of Act V, he fights to the death. Order is restored and the rightful king ascends to the throne.