At a camp near Sardis, Brutus and his generals enter. Brutus hints at some slight he has suffered at the hands of Cassius. He inquires of Lucilius how Cassius received him. Lucilius replies that he was greeted with respect but without the usual friendliness. Brutus interprets this to mean that his friendship with Cassius has grown cold and that he can no longer rely on it.
Cassius enters and accuses Brutus of wronging him. Brutus denies it, but does not want to dispute in front of their generals. He takes Cassius inside his tent so they can discuss the matter alone.
This scene moves the action forward and prepares the ground for the quarrel between Brutus and Cassius that is about to take place.