The nobleman Lennox discusses Scotland's plight with another lord. Isn't it weird that Duncan was murdered, that his run-away sons were blamed, that Banquo has now been murdered, that his run-away son (Fleance) is being blamed, and that everyone has a major case of déjà vu? Plus, the murders of Banquo and Duncan were too conveniently grieved by Macbeth, who had the most to gain from the deaths.
Lennox refers to Macbeth as a "tyrant," and then asks the other Lord if he knows where Macduff has gone off to.
Turns out Macduff has joined Malcolm in England.
Malcolm and Macduff are doing a pretty good job of convincing the oh-so gracious and "pious" King Edward of England, along with some English noblemen, to help them in the fight against Macbeth, the tyrant.