Hamlet stops and tells the ghost he will go no further. The ghost turns to Hamlet and instructs him to listen, as there isn't much time to talk. The ghost tells Hamlet that he is the spirit of his dead father. He is doomed to walk the earth at night and burn in hell by day. He demands that if his son loves him, he avenge his murder. The Prince pleads with his father to tell him who committed the crime so that he may seek revenge. The late King says that the crime had been committed by his brother Claudius, having won over the affections of the Queen, to obtain the crown. Claudius had slipped into the palace garden and poured poison into the ears of the sleeping king. Then, he passed the death off as being caused by a snakebite. The late King tells his son to seek revenge against Claudius but to leave his mother to face her punishment in the afterlife. The ghost exits and Hamlet swears revenge. Horatio and Marcellus arrive and Hamlet swears them to secrecy along with the disembodied voice of the ghost. Horatio and Marcellus swear the oath and the three men exit.
Hamlet: Novel Summary: Act 1, Scene 5