Macbeth Act IV, Scene iii Summary

Near King Edward's palace in England, Malcolm and Macduff discuss what to do about Scotland's plight under the tyrannous Macbeth. Malcolm suggests finding a nice shady spot where they can cry their eyes out. Macduff says he's got a better idea – he suggests that they whip out our swords and fight like "men" against the good-for-nothing Macbeth.
Malcolm says that's a good idea but he worries Macduff might have something to gain by turning on him, (Malcolm) and betraying him to Macbeth. Besides, Macduff doesn't seem like a loyal guy these days, having abandoned his family back in Scotland and all.
Macduff says he's loyal and trustworthy.
Still, Malcolm's a little paranoid so he decides to test Macduff by suggesting that even he, Malcolm, might make a poor king, were they to defeat Macbeth. Scotland would suffer, he says, under his own bad habits. Malcolm claims to have an impossible lust that would only get worse as he devoured all of the maidens of Scotland.
Macduff at first insists there are plenty of maidens in Scotland, and Malcolm would be satisfied.
Malcolm presses further about how bad he would be as king, and Macduff finally despairs that Scotland apparently is going to be in trouble either way.
Malcolm then relents because he sees Macduff is truly devoted to Scotland, not to a political alliance. Malcolm then admits that not only is he not lustful, he's never even "known" a woman.
Macduff and Malcolm are allied in the cause of taking Scotland back from Macbeth, and they have an army of ten thousand Englishmen at their backs, ready to fight and kill.
Then a doctor shows up (rather unexpectedly) and talks about how King Edward is tending to a crew of poor souls afflicted by a nasty disease called "scrofula," which the King heals with his touch. It's implied that it's helpful to have a genuine king, as he gets his power from God and can do cool stuff like cure diseases and rule with an iron fist.
We interrupt this program for a History Snack: Scrofula (what we now know is a form of tuberculosis that affects the lymph nodes and skin) was also called the "King's Evil" and it was thought to be cured by a little something called the "Royal Touch," a kind of laying on of hands ceremony that was performed by monarchs in France and England as far back as the middle ages. The healing ceremony was supposedly started in England by King Edward the Confessor (who's a swell king in Macbeth). In a book called The Royal Touch, historian Marc Bloch writes that King James I (who sat on the throne when Macbeth was first written and performed) wasn't exactly thrilled about performing this ceremony – he thought it was superstitious – but he did it anyway.
Then Ross, a Scottish nobleman, appears in England and has a chat with Malcolm and Macduff about how Scotland is in a bad way. Macduff asks after his family, and Ross initially says they are unmolested by the tyrant Macbeth. He adds that if Macduff were to return, Scotland might gather and take up arms against Macbeth. Malcolm promises when they finally arrive in Scotland, ten thousand English soldiers will come, too.
Ross then announces he has some bad news, actually. Macduff offers to guess at it, but before he does Ross blurts out that, contrary to what he said before, Macduff's family has been gruesomely murdered.
Macduff despairs and blames himself for leaving. Malcolm recommends that Macduff take his own advice and begin murdering out of revenge instead of crying. Macduff vows to slay Macbeth, committing to action instead of thought.

Act V, Scene i

Act IV, Scene ii