We're back with that rebel, Gloucester, who's led Lear, the disguised Kent, the disguised Edgar, and the Fool to a little building outside of his castle to get them all out of the storm.
Lear asks the philosophizing Edgar, who is still pretending to be the mad Poor Tom, a bunch of questions.
The Fool interjects occasionally, revealing that things must be really bad when the only person who makes sense in the conversation is the guy whose profession (as a licensed fool) dictates that his speech doesn't make any sense at all.
Lear's sanity spins downward. He imagines his daughters are in the room, and he demands that Poor Tom (a.k.a. Edgar), Kent, and the Fool enact a mock trial where he can charge his daughters with their crimes.
Lear gets so worked up – and so obviously not in his right mind – that even Edgar is jolted from his role-playing to feel pity.
Kent finally convinces Lear to lie down and get some sleep when Gloucester comes back again with bad news. There's definitely a plot against Lear's life, though Gloucester notably doesn't mention who's plotting.
Kent has to wake up Lear immediately and get him into a cart that can take him to safety in Dover, where Cordelia is. They have no time to waste, because if the plotters find Lear, his life and the life of anyone who helps him will be in danger.
Kent, Lear, the Fool, and Gloucester exit with the intention of getting Lear to safety, if not sanity.
Edgar leaves after them, filled with pity for Lear, whose pathetic situation makes Edgar feel better about his own.
Edgar admits that there's no greater suffering than mental illness.
Edgar also ponders that his life will be OK just as soon as the truth comes out that he's been plotted against and wrongfully condemned.