The hero, Hamlet, seeks vengeance against his father's murderer, his uncle Claudius, now the king of Denmark. Much of its fascination, however, lies in its uncertainties. Among them: What is the Ghost--Hamlet's father demanding justice, a tempting demon, an angelic messenger? Does Hamlet go mad, or merely pretend to? Once he is sure that Claudius is a murderer, why does he not act? Was his mother, Gertrude, unfaithful to her husband or complicit in his murder?