Macbeth Act 2, Scene 1
Banquo meets his son, Fleance, in the court of the castle in the middle of the night because he can't sleep. It's past midnight and Macbeth comes in. Banquo is surprised that Macbeth is still awake because Duncan is already in bed. Banquo tells Macbeth that he dreamed of the witches. Macbeth says that he wants to talk with Banquo sometime about the witches' prophecies. Banquo dodges the subject and is reluctant to discuss the predictions unless he can be sure that he can keep his conscience clear and maintain his loyalty to the king. Macbeth sends the reluctant Banquo off to bed then.
When Banquo and Fleance are gone Macbeth tells a servant to tell Lady Macbeth to prepare his "drink," which is the signal for drugging the soldiers outside Duncan's door.
As Macbeth waits for the signal from his wife, he imagines that he sees a dagger hovering in front of him. He sees the evilness of what is planned, but when the bell signals him to murder Duncan, Macbeth goes to complete the treachery against the king.