At the British battle camp near Dover, Edmund and Regan are engaged in what seems to be a heated conversation.
Regan keeps asking Edmund if he's done "it" with Goneril. Edmund swears on his honor that he has never done anything with Goneril. (Which is interesting considering that the man has no honor.)
Just as Regan orders Edmund to stay out of Goneril's bed, Goneril and her husband, Albany, abruptly enter.
The showdown between Cordelia's French troops and the British troops led by Albany, Regan, and Goneril is about to begin.
Albany notes that while the French troops are joined by Lear and many others with justifiable grievances against the state, Albany must still keep his country as a priority. As France is invading his land, he has to fight for it, even if he doesn't like his allies and he believes in the cause of his enemies.
Goneril suggests that they should get over their little domestic squabbles for some greater good.
She then continues her own personal domestic squabble with Regan over Edmund. Quietly fighting over the louse, the two sisters exit with him, neither trusting the other to be alone with Edmund.
Albany is left alone, an opportune moment for him to be approached by the disguised Edgar. Edgar gives Albany the letter he took from Oswald, demands Albany read it before the battle, and runs off without ever revealing his true identity.
Edmund comes back to give Albany an update about the battle preparations.
When Albany leaves, Edmund is left alone to gloat over his successes. "To both these sisters have I sworn my love… Which of them shall I take? / Both? One? Or neither?" he asks himself. He'll have to choose after the battle, he decides – or after Goneril kills her husband so she can be with him.
Edmund decides that if they manage to capture Lear and Cordelia, he'll have to make sure that Albany doesn't pardon them and restore them to power. Edmund wants them out of the way so that he can take control of the kingdom.