The ghost appears to Hamlet and indicates that it wants to speak to him alone. Horatio and Marcellus try to stop him but Hamlet follows the ghost.
The ghost tells Hamlet that Claudius murdered him and gives Hamlet the task, which he accepts, of taking vengeance on Claudius without harming Gertrude. Hamlet refuses to tell Horatio and Marcellus what happened with the ghost. He swears them to secrecy. Hamlet curses the fates for imposing the terrible burden he now has to carry.
Polonius wants to find out how Laertes is behaving in Paris and sends a servant to spy on him. Ophelia reports that Hamlet visited her in a distressed state. Polonius and Ophelia believe that Hamlet has gone mad with grief because Ophelia has been keeping him at a distance.