King Lear — Act 4, Scene 5: Gloucester's castle.

At Gloucester’s castle, Regan questions Oswald about whether her brother’s forces have already marched and whether Edmund was seen with them. She learns that Edmund has gone off urgently and that Goneril wrote to him privately. Suspicious, Regan presses Oswald to show her the letter, but he tries to refuse because Goneril charged him with it. Regan openly grows jealous, accusing her sister of loving Edmund and no longer caring for Albany, and she declares that Edmund would suit her better. She gives Oswald a message and asks him to carry news to Goneril. Before he goes, she urges him to hunt down the blind Gloucester if he can.