Edgar talks to himself on the heath, reflecting that his situation is not as bad as it could be. He is immediately presented with the horrifying sight of his blinded father. Gloucester is led by an old man who has been a tenant of both Gloucester and Gloucester’s father for eighty years. Edgar hears Gloucester tell the old man that if he could only touch his son Edgar again, it would be worth more to him than his lost eyesight. But Edgar chooses to remain disguised as Poor Tom rather than reveal himself to his father. Gloucester asks the old man to bring some clothing to cover Tom, and he asks Tom to lead him to Dover. Edgar agrees. Specifically, Gloucester asks to be led to the top of the highest cliff.

Goneril and Edmund arrive outside of her palace, and Goneril expresses surprise that Albany did not meet them on the way. Oswald tells her that Albany is displeased with Goneril and Regan’s actions, glad to hear that the French army had landed, and sorry to hear that Goneril is returning home.

Goneril realizes that Albany is no longer her ally and criticizes his cowardice, resolving to assert greater control over her husband’s military forces. She directs Edmund to return to Cornwall’s house and raise Cornwall’s troops for the fight against the French. She informs him that she will likewise take over power from her husband. She promises to send Oswald with messages. She bids Edmund goodbye with a kiss, strongly hinting that she wants to become his mistress.

As Edmund leaves, Albany enters. He harshly criticizes Goneril. He has not yet learned about Gloucester’s blinding, but he is outraged at the news that Lear has been driven mad by Goneril and Regan’s abuse. Goneril angrily insults Albany, accusing him of being a coward. She tells him that he ought to be preparing to fight against the French invaders. Albany retorts by calling her monstrous and condemns the evil that she has done to Lear.

A messenger arrives and delivers the news that Cornwall has died from the wound that he received while putting out Gloucester’s eyes. Albany reacts with horror to the report of Gloucester’s blinding and interprets Cornwall’s death as divine retribution. Meanwhile, Goneril displays mixed feelings about Cornwall’s death: on the one hand, it makes her sister Regan less powerful; on the other hand, it leaves Regan free to pursue Edmund herself. Goneril leaves to answer her sister’s letters.

Albany demands to know where Edmund was when his father was being blinded. When he hears that it was Edmund who betrayed Gloucester and that Edmund left the house specifically so that Cornwall could punish Gloucester, Albany resolves to take revenge upon Edmund and help Gloucester.

In these scenes, the play moves further and further toward hopelessness. We watch characters who think that matters are improving realize that they are only getting worse. Edgar, wandering the plains half naked, friendless, and hunted, thinks the worst has passed, until the world sinks to another level of darkness, when he glimpses his beloved father blinded, crippled, and bleeding from the eye sockets. Gloucester, who seems to have resigned himself to his sightless future, expresses a similar feeling of despair in one of the play’s most famous and disturbing lines: “As flies to wanton boys are we to the gods; / They kill us for their sport” (IV.i.37–38). Here we have nihilism in its starkest form: the idea that there is no order, no goodness in the universe, only caprice and cruelty. This theme of despair in the face of an uncaring universe makes King Lear one of Shakespeare’s darkest plays. For Gloucester, as for Lear on the heath, there is no possibility of redemption or happiness in the world—there is only the “sport” of vicious, inscrutable gods.

It is unclear why Edgar keeps up his disguise as Poor Tom. Whatever Edgar’s (or Shakespeare’s) reasoning, his secrecy certainly creates dramatic tension and allows Edgar to continue to babble about the “foul fiend[s]” that possess and follow him (IV.i.59). It also makes him unlikely to ask Gloucester his reasons for wanting to go to Dover. Gloucester phrases his request strangely, asking Tom to lead him only to the brim of the cliff, where “from that place / I shall no leading need” (IV.i.77–78). These lines clearly foreshadow Gloucester’s later attempt to commit suicide.

Meanwhile, the characters in power, having blinded Gloucester and driven off Lear, are swiftly becoming divided. The motif of betrayal recurs, but this time it is the wicked betraying the wicked. Cornwall has died, and Albany has turned against his wife, Goneril, and her remaining allies, Regan and Edmund. Albany’s unexpected discovery of a conscience after witnessing his wife’s cruelty raises the theme of redemption for the first time, offering the possibility that even an apparently wicked character can recover his goodness and try to make amends. Significantly, Albany’s attacks on his wife echo Lear’s own words: “O Goneril! / You are not worth the dust which the rude wind / Blows in your face,” Albany tells her after hearing what she has done to her father (IV.ii.30–32). Like Lear, Albany uses animal imagery to describe the faithless daughters. “Tigers, not daughters, what have you performed?” he asks (IV.ii.41). Goneril, for her part, is hardly intimidated by him; she calls him a “moral fool” for criticizing her while France invades (IV.i.59). Goneril equates Albany’s moralizing with foolishness, a sign of her evil nature.

When Albany hears that Cornwall is dead, he thanks divine justice in words that run counter to Gloucester’s earlier despair. “This shows you are above, / You justicers,” he cries, offering a slightly more optimistic—if grim—take on the possibility of divine justice than Gloucester’s earlier comment about flies, boys, and death (IV.ii.79–80). His words imply that perhaps it will be possible to restore order after all, perhaps the wicked characters will yet suffer for their sins—or so the audience and characters alike can hope.