Hamlet devises a play in order to gauge Claudius's reaction to the performance. In this way, Hamlet can confirm the revenge plot revealed by the ghost of his father, rather than simply rely on the information of a spectral figure. Hamlet informs Horatio that, in the case of Claudius exhibiting no reaction, he will conclude that he had been fooled by a "damned ghost" rather than the spirit of his true father.

Hamlet informs Claudius that the performance is called The Mousetrap. This can be interpreted as Claudius being a lowly mouse/creature who is caught in Hamlet's clever trap. Hamlet refers to Claudius multiple times as beastly, so this is fitting. Claudius's emotional reaction convinces Hamlet of his guilt, setting in motion the climax of the play in which Hamlet kills Claudius, as well as Hamlet's death. Claudius and Laertes had conspired to murder Hamlet and the plot is executed by Laertes.

Shakespeare uses the "play within a play" device as a means for Hamlet to proclaim Claudius' guilt. Using a travelling troup of players for his own purposes, Hamlet arranges for them to include in their production an enactment in pantomime of his father's murder and a revealing and pointed dialog between the Player King and the Player Queen in regard to the Queen's remarriage after the King's death. Hamlet asks Horatio to watch Claudius during this scene to see how he reacts to the performance he witnesses as it plays out before the assembled guests. Claudius' discomfort grows until he departs suddenly. Hamlet believes he has exposed Claudius' guilt.