The play’s the thing wherein I’ll catch the conscience of the King.
Travelling players have arrived at Elsinore. After watching an actor weep over fictional Hecuba, Hamlet is shamed by his own inaction. He devises a plan: have the players perform a scene mirroring his father’s murder. If Claudius flinches, the Ghost spoke true.
Hamlet’s plan crystallizes: use a play to test Claudius’s guilt. Theatre becomes a weapon for truth.