Scottish noblemen, including Lennox, Menteth, Cathness and Angus converge in the country near Dunsinane, where Macbeth keeps his castle. We learn from Menteth that on their heels is the English army, led by Malcolm, his Uncle Siward, and Macduff. They'll all meet up near Birnam Wood. (Sound familiar?) We learn that Donalbain is not with his brother and that a great many young men have taken up arms with the English army.
Cathness informs the group that the tyrant King is hell-bent on protecting Dunsinane, and though Macbeth is thought mad by some, and valiant by others, it's quickly becoming clear that his actions are in his own interests and not the nation's. Everyone agrees that Macbeth's a lousy king and needs to go. They all agree to fight wholeheartedly for Scotland.