Duncan arrives at Macbeth's castle with his sons as well as other nobles.
Lady Macbeth graciously greets King Duncan as he enters the castle, as he comments on her honor as a hostess. He offers her his arm as she leads him around the castle.
In another room, Macbeth contemplates his and Lady Macbeth's plans to kill Duncan in order to fulfill the prophecy. He doesn't want to betray Duncan as he believes him to be a good king who he is loyal to.
Lady Macbeth finds her husband and asks what he is waiting for, why hasn't he killed the king. He responds by explaining the logical reasons why they shouldn't kill the king. Lady Macbeth insults his masculinity and guilts him into killing Duncan by saying she would do the same thing for him, she even says she would go as far as killing her own child for him.
Macbeth frantically leaves to kill Duncan after getting his guards drunk in order to have easy access to the King.