Claudius ends up finding out that Hamlet has assassinated Polonius from Gertrude, which leads to Claudius drive to send Hamlet over to England before people hear about the death.
Act 4 Scene 4
After the murder Rosencrantz and Guildenstern attempt to get Hamlet to confess where he has left Polonius corpse, however, they are unsuccessful.
Act 4 Scene 5
Claudius is attempting to make Hamlet tell him where he placed Polonius body, moreover, he is sending letters with Rosencrantz and Guildenstern to the English King in order for him to order an execution for Hamlet.
Act 4 Scene 6
Hamlet has a confrontation with the captain of the Norwegian, which was invading Poland. As Hamlet sees the soldiers marching he reflects on how he hasn't taken action towards his own goals.
Ophelia begins to sing bawdy songs, due to the death of her father. Moreover, Laertes is angry for the improper burial of his father. Claudius promises Laertes that he will tell him the truth of what happened with his father.
Sailors deliver a letter to Horatio from Hamlet explaining that Hamlet's ship was besieged by pirates and Hamlet alone has been returned to Denmark.