Macbeth Act III, Scene iv Summary

Meanwhile, back at the dinner party, Macbeth, Lady Macbeth, Ross, Lennox, other lords, and attendants are about to share the new King's celebratory meal. Macbeth makes a big show of welcoming everyone, as does Lady Macbeth.
The first murderer enters as everyone is being seated. Macbeth darts off to see the first murderer, who informs him that they've slit Banquo's throat, but that Fleance has escaped.
Macbeth laments the loss, as now Banquo is dead, but Macbeth's fear lives on in Banquo's son, heir and threat to Macbeth's newly won throne. He says Fleance is but yet a young snake, and time will surely make him grown venomous with revenge. In the meantime, at least Banquo is dead. The murderer is sent off, and Lady Macbeth calls Macbeth back to the party.
And now the fun begins: Banquo's ghost shows up. Because the ghost is silent, he gets to creep around quite a bit before anyone notices. While everyone is busy not noticing, Macbeth raises a toast and calls special attention to Banquo's absence as unkindness or mischance on Banquo's part. This is particularly hilarious given the presence of…Banquo's ghost.
Again Macbeth is invited to sit, and in the spot they've reserved for him sits…Banquo's ghost. Naturally, Macbeth goes into a fit, and the lords all take notice, while Lady Macbeth excuses him for these "momentary" fits he has had since childhood. She urges them to keep eating, and then corners Macbeth, who is still hysterical.
Lady Macbeth asks if Macbeth is a man, because he's not acting like one so much as he is acting like a sissy. Lady Macbeth dismisses the vision as a painting of his own fear. Meanwhile, Macbeth is discoursing with the ghost that only he sees, and it disappears.
Macbeth notes it is unnatural for murdered men to not stay murdered. He is also still pretty wired. At Lady Macbeth's chiding, he apologizes to the group for his momentary fit and seems normal again until the ghost shows up once more. Again Macbeth calls out a toast to the missing Banquo (he's just asking for it now) and noting the ghost, screams out at him that if he appeared in any other form, Macbeth's nerves would not tremble.
After some challenging along this line, it's pretty clear the party's over, and though Macbeth tries to recover, he scolds everyone else for seeming to be so calm in the face of such a horrible sight.
Lady Macbeth tells the now very worried lords to leave immediately, and as they exit, Macbeth philosophizes that blood will have blood.
Morning is now approaching, and Macbeth points out that Macduff never showed at the party. He lets out that he has had a spy in Macduff's house. He promises to go to the witches the next day, and announces that he's in so deep a river of blood, it would be as hard to go back as to cross.
Lady Macbeth, wearied, insists he just lacks sleep. The scene concludes with Macbeth suggesting that his fears are just the effect of being young at the murdering/tyranny game. They go to bed, with more murder to follow.

Act III, Scene v

Act III, Scene iii