Ross and an old man stand near Macbeth's castle. They discuss the unnatural portents just before and after Duncan's murder: darkness during the day, owls killing hawks, horses eating one another.
Further havoc in nature caused by the murder of Duncan and destruction of the natural order.
Macduff enters. He says it seems Duncan's attendants did commit the murder, and that because Malcolm and Donalbain fled they likely were behind the plot.
Macbeth's plot worked! If he could be a good and virtuous King, perhaps it will all turn out well…
Macduff then says Macbeth has been made king, and that he has already gone to Scone for the coronation. Ross heads to the coronation. But Macduff returns to his own castle at Fife.
…but does Macduff suspect him already? It isn't clear. But the paranoid Macbeth must think he does: violence creates fear which leads to violence.