Hamlet lectures three of the players on how to act. His lecture focuses on how to avoid overacting, suiting action to word and word to action. They exit.
Hamlet instructs actors how to bridge the gap between appearance and reality!
Hamlet has already told Horatio what the Ghost said, and now reveals his plan: the play to be put on will mirror the Ghosts' description of Claudius's murder of Old Hamlet. If Claudius looks guilty while watching it, then he is.
Hamlet plans to use the "appearance" of the play to simulate "reality" in order to prove if that reality is really real. Then, he says, he'll take revenge.
Claudius, Gertrude, Polonius, Ophelia, and others arrive to watch the play. Hamlet tells Horatio he's now going to act insane.
Hamlet puts on a "play" of his own—he pretends to be insane.
Claudius asks how Hamlet is faring. Hamlet responds as if Claudius were using the word "fare" to mean food, and says he's eating the air. Hamlet mocks Polonius's attempts to act at university, harasses Ophelia with sexual puns, then makes bitter remarks about Gertrude for marrying Claudius.
Once again, Hamlet's anger at women pushes his pretend madness toward something less pretend.
The players enter and first act out a dumbshow (a short silent play that shows what the longer play is about). The players then begin to act the full play. As the plot becomes clear, Gertrude and Claudius become uncomfortable. Hamlet mocks them, while continuing to launch sexual puns at Ophelia. Claudius asks the name of the play. Hamlet says, "The Mouse-trap."
If Hamlet is using madness only to try to protect himself from suspicion, why does he mock the King and Queen so obviously? And why mock Ophelia at all?
When the villain in the play pours poison into the king's ear, Claudius jumps from his seat, calls for light, and rushes from the room.
Claudius' reaction reveals that he really is guilty.
Hamlet is triumphant. He tells Horatio that this proves the Ghost was telling the truth.
Hamlet's fear that Ghost was lying delayed his revenge.
Rosencrantz and Guildenstern enter and say that his mother wants to see him. Hamlet agrees to go, but furiously tells them they cannot "pluck out the heart of his mystery" or play him like a flute (3.2.336).
R and G try to use the guise of friendship to learn Hamlet's thoughts. Such dishonesty angers Hamlet.
Polonius enters, repeating Gertrude's request to see him. Hamlet pretends to see odd shapes in a non-existent cloud. Polonius also pretends to see the shapes.
Hamlet shows that Polonius will lie to flatter those who are more powerful than he.
All exit but Hamlet, who says to himself that he could "drink hot blood" (3.2.360), but forces himself to remember not to hurt his mother.
Hamlet knows he has no reason to delay revenge now, and shows that he knows his anger at women is out of control.