Macbeth: Plots for Murder In William Shakespeare's Macbeth, there are many plots for murder. The murder of Duncan has a significant impact on Macbeth. He, along with his "sleep" is never the same after this event. After the murder of Duncan, his innocence is gone and he decides that no one is going to stand in his way of being king. Thus, when he feels threatened by Banquo and the prophesies of the witches, he plots to kill him and his son Fleance. Macbeth arranges for two men to murder Banquo and his son. However, when the actual event occurs a third murderer appears. This third murderer's identity is