King Duncan wins a great battle and Macbeth becomes a hero!
On the way home from battle they spot three witches. Curious and suspicious the two men proceed to talk to them. They told Macbeth that he will be Thane of Cowdor, then King. The three witches also prophesied that Banquos descendants will be King.
Macbeth writes a letter to Lady Macbeth, telling her what the witches said about him and Banquo becoming King.
I can't have him take my place. The witches told me so!
Macbeth and Lady Macbeth plot to kill King Duncan. He soon comes to stay the night at Macbeths castle.
Lady Macbeth persuades Macbeth to go ahead with the murder. He murders King Duncan that night.