What is a summary for act one of Hamlet?
In act I we meet Hamlet and find out that his father, the King of Denmark, has been killed, and his Uncle Claudius has taken the throne. Claudius has also married Hamlet's mother, Gertrude.
The ghost of Hamlet's father appears, tells Hamlet that Claudius killed him, and asks Hamlet to take revenge.
Check out the video summary or the text summary on enotes for more info.