- The ghost of Hamlet's father appears to Hamlet and reveals that he was murdered by Hamlet's uncle Claudius. Hamlet vows revenge against Claudius.
- Hamlet puts on a play mimicking the murder to prove Claudius' guilt, which causes Claudius to react with guilt. Hamlet also confronts his mother about remarrying.
- In the chaos, Hamlet accidentally kills Polonius, thinking it is Claudius. Claudius sends Hamlet away, but plans are changed when Hamlet returns earlier than expected. Claudius and Laertes plot to kill Hamlet during a fencing match using a poisoned blade and poisoned wine.