Rosencrantz & Guildenstern came to spy Hamlet. The ambassadors return from a successful mission. Polonius tells Claudius & Gertrude that Ophelia's rejection may be Hamlet's strange behaviour. Hamlet meets Rosencrantz & Guildenstern with real purpose of visit and they abandon to detect the cause of his discontent. Theatrical company arrives and a player performs a speech at Hamlet's request. He decides to use a play to test the ghost's story and establish Claudius's guilt.
Rosencrantz & Guildenstern admit to Claudius that they have failed to find a cause for Hamlet's lunacy. The idea advanced by Polonius that Hamlet's madness was caused by Ophelia's refusal to meet him is tested. Claudius concludes that Hamlet is neither lovesick nor mad. He decides to send Hamlet to England.
Claudius, Gertrude, Polonius, Horatio, Hamlet & Ophelia are all present to watch a play. The main elements of both are the poisoning of a king and the marriage of the poisoner to the king's widow. Claudius rises in alarm. Polonius halts the performance. Hamlet is now convinced of the truth of the ghost's story. Gertrude sends for Hamlet to come to her apartment.