Uh-oh. Anybody who has read Henry IV Part 1 (or lives in seventeenth-century England) knows it's not a good idea for Lear to split up the kingdom so he can enjoy an early retirement. We wonder what will happen next…
Lear decides to divide his kingdom based on which of his daughters professes the most love for him. The love-game doesn't go so well, and Cordelia ends up disowned. Kent is similarly banished, and Edmund decides to be evil. We have political and personal conflicts here.
Lear's daughters (Goneril and Regan, that is) aren't exactly hostess material, and Lear is most definitely a lousy guest so, there's some serious domestic drama coming to a head at this point.
Furious at the ingratitude of his children, Lear walks out on both of them and wanders screaming into the thunderstorm. Thunder and lightning are pretty strong indicators of the climax, as is Lear's searing language and emerging insanity. Gloucester also gets his eyes plucked out when he tries to help Lear and Edmund rats him out.
As Cordelia's French troops march somewhere offstage, tension builds. Also, with everyone wearing disguises and concealing their true identities, it's only a matter of time before the truth is revealed. But until that happens, we can feel the tingly anticipation of waiting for it.
Lear and Cordelia lose the battle and are imprisoned. Lear, wiser now than at the beginning of the play, says he doesn't mind – he's learned over the course of the play that power politics don't matter, while a good relationship with his daughter does. But then Cordelia is hanged.
Heartbroken, Lear dies while cradling his daughter in his arms. Somebody obviously has to take over the kingdom now, but nobody really wants to the job.