The impossibility of certainty.
Hamlet Sr. tells Hamlet Jr. the true story of how he was murdered and tells his son to avenge him.
Denmark is the setting.
Hamlet is the protagonist.
Claudius is the antagonist.
Hamlet plotting to kill Claudius is the rising action.
Hamlet going crazy after killing Polonius is the climax.
Hamlet being sent to England to unknowingly be killed and then returning to Denmark after figuring it out and confronting Laertes is the falling action.
The death of the royal family is the resolution.