A nobleman named Kent speaks up in defense of Cordelia, but the king banishes him. Another nobleman, Gloucester, introduces his illegitimate son Edmund and tells him that he is not entitled to any inheritance. Edmund is resentful and decides to plot against his legitimate half-brother Edgar, who is Gloucester's true heir.

Meanwhile, the king goes to live with Goneril, but she quickly becomes annoyed with his behavior and demands that he reduce the size of his entourage. The king is shocked and angry at her ingratitude and decides to leave and go to Regan's house instead.

Overall, Scene 1 sets up the main conflicts of the play: the struggle for power among the king's daughters, the tension between legitimate and illegitimate heirs, and the consequences of pride and stubbornness.

Edmund forges a letter from Edgar that suggests he is planning to kill Gloucester, and then shows it to his father. Gloucester is convinced by the letter and immediately believes that Edgar is a traitor. Edmund uses this opportunity to turn his father against his own brother and gain favor for himself.

As the scene progresses, Edgar enters and is confused by his father's anger towards him. He is unaware of the letter and the accusations against him. Gloucester tells Edgar to flee and never return, believing him to be dangerous and disloyal. Edgar is forced to flee and disguise himself as a beggar to avoid being caught.

The scene ends with Edmund expressing his satisfaction at having successfully turned his father against his brother and gained power and status for himself. The audience is left wondering how Edgar will survive and if he will ever be able to clear his name.

Just then, Lear and his entourage enter. Lear is furious with Kent for speaking out against his decision and banishes him from the kingdom. Kent protests, but Lear will not listen. He then turns his attention to his daughters and asks them to profess their love for him in order to receive their share of the kingdom.

Goneril, Lear's eldest daughter, delivers a long-winded speech professing her love for her father. Lear is pleased and gives her the largest share of the kingdom. Regan, Lear's middle daughter, follows suit with a similar speech and is also rewarded with a share of the kingdom. However, when it is Cordelia's turn, she refuses to flatter her father and profess her love in such a way. Lear becomes enraged and disowns her, splitting her share of the kingdom between Goneril and Regan.

The scene ends with Kent, who has disguised himself as a servant, pledging to follow Lear and serve him faithfully despite his banishment.

Lear arrives with his retinue of knights and immediately begins to argue with Goneril. He accuses her of being ungrateful and disrespectful, and tells her that he will go to his other daughter, Regan, instead. Goneril responds by telling Lear that he is being irrational and that he needs to listen to her advice.

Regan arrives with her own retinue of knights, and Lear is pleased to see her. However, Regan immediately sides with Goneril and tells Lear that he needs to be more reasonable. Lear becomes angry and tells Regan that she is ungrateful just like her sister.

The argument between Lear and his daughters continues to escalate, with both sides becoming increasingly hostile. Eventually, Lear decides to leave and go back out into the storm. Goneril and Regan are left behind, feeling frustrated and resentful towards their father.

As the scene progresses, the king's advisors express their concern about the division of the kingdom and the possibility of conflict between the sisters. However, the king dismisses their concerns and sets out to enjoy the hospitality of his daughters. The scene ends with the king reflecting on his decision to divide his kingdom and expressing his hope that his daughters will continue to love and care for him.

Overall, Scene 5 of Act 1 is a tense and dramatic scene that sets the stage for the conflict and tragedy that will unfold in the rest of the play. It highlights the themes of love, power, and family relationships, and introduces the complex and flawed characters who will drive the action of the play.

Edmund then forges a letter from Edgar, in which Edgar appears to plot against their father's life. Edmund shows the letter to Gloucester, who is horrified and decides to have Edgar arrested. Edmund, pleased with his success, plans to use the situation to further his own ambitions.

The scene establishes Edmund as a cunning and ambitious character, willing to deceive and manipulate to achieve his goals. It also sets up the conflict between Gloucester's two sons and foreshadows the chaos that will ensue as the play progresses.

Edmund then delivers a soliloquy in which he reveals his true intentions: to use his father's trust to gain power and to discredit his half-brother. He plans to forge a letter from Edgar, which will make it seem as though he is conspiring against their father. Edmund is an ambitious and ruthless character who will stop at nothing to achieve his desires.

The scene ends with Edmund leaving to carry out his plan, leaving Gloucester grappling with his conflicting emotions and worries about the future. The themes of power, deception, and family relationships are heavily present in this scene, setting the stage for the tragic events to come.

During their conversation, Gloucester also tells Edmund about King Lear's plan to divide his kingdom among his daughters. Edmund sees this as an opportunity to gain power and suggests that if he were in Lear's position, he would not divide his kingdom so easily. Gloucester agrees, but also notes that Lear is an old man and may not be thinking clearly.

Overall, this scene sets the stage for the betrayal and deception that will occur later in the play. It also highlights the theme of filial ingratitude, as Gloucester is willing to believe the worst about his own son and Edmund is willing to betray his own brother for personal gain.