The “The play is the thing, wherein I’ll catch the conscience of the king.” dialogue is used in Shakespeare’s play, Hamlet, in Act 2, Scene 2. These lines were spoken by Hamlet himself. Hamlet is trying to know the truth about his father’s death. He doubts that his uncle, King Claudius, murdered his father. He decided to incorporate events related to his father’s murder in his play, which according to him will trigger king in making reaction, in case he is guilty. You may use this quote, when you plan something to trigger reactions.