Lear, king of Britain, divides his kingdom among his three daughters, making his gifts dependent upon each daughter's declaration of love for him. The two oldest, Goneril and Regan, gush sweet adjectives in their greed, but young Cordelia, in her integrity, refuses to allow so intimate a truth to be flaunted for public hearing, and says she loves him neither more nor less than the natural bond of daughter to father dictates. Furious, Lear disinherits her, gives all his lands and powers to Goneril and Regan, and makes plans to live alternately a month at a time with them. The earl of Kent tries to intercede and is banished. Dowerless Cordelia marries the king of France and flees to his country.
At the same time, the earl of Gloucester is deceived by the false sincerity of his illegitimate and wicked son, Edmund, who has forged a letter attempting to deprive his brother, Edgar, of his birthright and who has convinced Gloucester that Edgar is going to murder his father. Also, Kent, instead of going into exile, returns in disguise to become a servant of his old master and arrives at Goneril's castle as she is beginning to insult and shame her father. Cursing his eldest daughter, King Lear departs immediately for Regan's, sending the disguised Kent ahead.
Meanwhile, Regan and her husband, the duke of Cornwall, go to Gloucester's castle, where for a minor offense and to humiliate Lear, they put the disguised Kent into the stocks. There he is found by the king, who is accompanied by his loving, but bitter, fool. Regan refuses to take in her father until he has made apology to her sister. Goneril arrives, and Lear perceives that the daughters are in league, and he sets out into the night.
On the stormy heath, Lear, with his fool, hurls defiance at the elements and, joined by Kent, who has now been released from the stocks, seeks refuge in a hovel which is already occupied by noble Edgar, disguised as mad Tom O'Bedlam. Just as Kent has composed the king (who is showing signs of going mad),
Gloucester arrives with word that the daughters are plotting against the king's life, and that he must be taken to friends at Dover. Meanwhile, the duplicitous Edmund has furnished evidence that Gloucester has been assisting Cordelia's invasion from France. As a result, Cornwall captures Gloucester and plucks out his eyes, but in the process he is mortally wounded by Gloucester's faithful servant.
In the open country Edgar finds his blind father and, without revealing himself, becomes his guide. Cordelia, who has returned with the armies of France to fight her sisters, finds her mad father and cares for him. Meanwhile, the duke of Albany denounces his wife, Goneril, for her cruelty; the two older sisters add lust for Edmund to their crimes; and Edmund becomes commander-in-chief of the English forces.
Albany joins armies with Edmund only to protect Britain, and in battle the French are defeated. Lear and Cordelia become Edmund's prisoners, and he sends them to prison to be executed. Jealous of her love for Edmund, Goneril poisons Regan and then stabs herself when her own crimes are found out. Albany arrests Edmund for treason, and in formal combat Edgar mortally wounds his brother. Before he dies, he tries to do good, "despite his nature," by countermanding his order to hang Cordelia, but it is too late. Lear enters with her body in his arms, and immediately dies himself, happy in knowing that one of his children truly loves him. Gloucester recognizes the virtues of Edgar, but still he crawls off to die of a broken heart, and Edgar and Albany are left to restore the kingdom.