Macbeth bids all the lords welcome to the feast. Just at that moment, he notices that one of the murderers is standing at the door. The murderer tells Macbeth that Banquo is dead but Fleance escaped. Macbeth comforts himself that Fleance will not be a threat for quite some time.
Macbeth learns that his first attempt to control fate has failed.
Lady Macbeth calls to Macbeth and asks him to return to the feast and sit. But Macbeth doesn't see an empty seat at the table. When Lennox gestures at a seat, saying it's empty, Macbeth sees Banquo's ghost sitting there. Macbeth alone can see the ghost. He astonishes the thanes by shouting at the empty chair.
Is Banquo's ghost real or a figment of Macbeth's guilty mind? The uncertainty emphasizes that Macbeth's fate is part of him, caused by his character: his ambition and guilt.
Lady Macbeth tells the thanes not to worry, that since childhood Macbeth has suffered fits. She pulls Macbeth aside and once again questions his manhood. The ghost disappears. Macbeth rambles about murders and spirits risen from the grave until Lady Macbeth reminds him of his guests. He echoes her story about his fits, then leads a toast to the missing Banquo.
Macbeth and Lady Macbeth continue to try to lie to keep their secrets and hold on power, but these lies become less and less effective as guilt about the violence they have committed begins to affect them.
The ghost reappears and Macbeth, terrified, starts shouting at it. Lady Macbeth tries to play down her husband's strange behavior. The ghost again disappears. Macbeth is amazed that everyone could be so calm in the face of such sights. When Ross asks what sights, Lady Macbeth steps in and asks the guests to leave at once. The thanes exit.
Macbeth has become so warped he cannot tell the unnatural from the natural anymore. Lady Macbeth sees lying is useless and chooses isolation: she tells the thanes to leave.
Macbeth tells Lady Macbeth: "Blood will have blood" (3.4.121), and asks what Lady Macbeth makes of the fact that Macduff does not appear at the royal court. He decides to visit the weird sisters to find out more about his fate.
Macbeth's desperation to keep power motivates him to visit the weird sisters. He has sacrificed everything for his ambition…
He says: "I am in blood / Stepped in so far" (3.4.135) that turning back is as difficult as continuing on.
… now ambition and violence are all he has left, and he knows it.