Edgar is just about to lead Gloucester to a place of safety and comfort when Oswald appears. Oswald is on his way to deliver Goneril’s letter to Edmund when he sees Gloucester. Regan had earlier told Oswald that she would reward him well if he should kill Gloucester, and so the servant rejoices in his good luck at finding the blinded earl.
Oswald does not think that Edgar will be of any trouble or hindrance to him. Edgar, after all, is not dressed as a gentleman and does not carry any weapon. Edgar, speaking in the regional dialect of the poor folk of that part of England, blocks Oswald from approaching Gloucester. Oswald threatens Edgar and draws out his sword. Edgar knocks the sword away and fights with Oswald. Eventually Edgar is able to defeat and kill Goneril’s unctuous servant.
With his dying breath, Oswald asks Edgar to deliver the letter that he is carrying to Edmund.
Oswald then dies.
Edgar takes the letter and reads it. In it Goneril not only writes about her intention to marry Edmund, but she also suggests to Edmund that when he finds time and opportunity, he is to murder Albany. Goneril tells Edmund that she will not be able to reward him properly as long as Albany remains alive.
Edgar is shocked to read that Goneril would allow her desires (suggested by the word will at line 266) to move her to such underhanded and despicable acts of betrayal against her own husband. However, Edgar plans to inform Albany of this betrayal and to show him the letter as proof.