The Mousetrap

In this scene, Hamlet found out a way to see if Claudius killed his father.  He found a group of traveling actors and he wants them to do a play for Claudius and the queen.  In this play, the actors will act a play in which the king has been murdered by his brother and marries the queen.  Only Horatio and Hamlet know of this plan.

Hamlet: I have met these group of traveling actors and I thought of a magnificent plan to see if Claudius killed my father.  They will act out a play where the king has been murdered by his brother and become king and marry the queen.  If Claudius reacts to this play, then I will know that he has killed my father.  The only other person who knows about this is Horatio.