Now that Macbeth is king he knows the second prediction from the witches has come true, but he starts to fear the third prediction (that Banquo's descendants will also be kings). Macbeth therefore decides to kill Banquo and his son, but the plan goes wrong - Banquo is killed but his son escapes. Macbeth then thinks he is going mad because he sees Banquo's ghost and receives more predictions from the witches. He starts to become ruthless and kills the family of Macduff, an important lord. Macbeth still thinks he is safe but one by one the witches' prophecies come true, Lady Macbeth cannot stop thinking about Duncan, becomes deranged and dies. A large army marches on Macbeth's castle and Macbeth is killed by Macduff.