How does the play in Act III, Scene 2 serve Hamlet's purpose?
At the end of Act II, Hamlet informs the audience of his plot to ascertain that the Ghost's story was true, and that Claudius really is guilty of his father's murder. He says that "the play's the thing/wherein I'll catch the conscience of the king." He plans to have the actors perform a play that bears a striking resemblance to the circumstances of his father's death, as the Ghost described it. In short, an assassin will murder a sleeping king by pouring poison in his ear, and then will claim his crown. Hamley believes that if the King is guilty, he will react with horror at the play. Just as he plans, Claudius is stunned by the play, and departs the hall in great anger. Hamlet remarks to Horatio, who was privy to his plan: "O good Horatio, I'll take the ghost's word for a thousand pound!" His suspicions confirmed, he goes off to confront his mother.