Hamlet rejects Ophelia, proving to Polonius and Claudius that she is not the source of his strange behavior.
To be or not to be, that is the question...
Rosencrantz and Guildenstern report to Claudius and Gertrude and say that they could not discover the cause of Hamlet's madness. They also tell them of a group of players that are coming and that Hamlet wants Claudius and Gertrude to attend, who accept.
Hamlet has the players recreate a scene of how the ghost told Hamlet that Claudius murdered him in order to see if Claudius is guilty. Claudius becomes very upset and storms out, proving that he is guilty to Hamlet.
Claudius delivers a soliloquy on his guilt about killing his own brother. He contemplates praying, but thinks that it will not work since he is still reaping the rewards of his sin. In the end, he decides to so that he can ease his conscience.
Hamlet gets ready to kill Claudius as he is praying but realizes that if he does then it will only send his soul to heaven. He then vows to kill him while he is sinning so that he goes to hell.
Hamlet confronts his mother about the murder of his father and she becomes distraught. When this happens, Polonius, hiding behind a tapestry, cries out. Hamlet discovers him and stabs him for eavesdropping.