Hamlet by William Shakespeare

The Tragedy of Hamlet, Prince of Denmark is a tragedy by William Shakespeare. Set in the Kingdom of Denmark, the play dramatizes the revenge Prince Hamlet exacts on his uncle Claudius for murdering King Hamlet, Claudius's brother and Prince Hamlet's father, and then succeeding to the throne and taking as his wife Gertrude, the old king's widow and Prince Hamlet's mother. The play vividly portrays both true and feigned madness – from overwhelming grief to seething rage – and explores themes of treachery, revenge, incest, and moral corruption.
Hamlet is William Shakespeare's longest play and among the most powerful and influential tragedies in the English language, with a story capable of "seemingly endless retelling and adaptation by others."
The protagonist of Hamlet is Prince Hamlet of Denmark. The story opens on a chilly night at Elsinore, the Danish royal castle. Francisco, one of the sentinels, is relieved of his watch by Bernardo, another sentinel, and exits while Bernardo remains. A third sentinel, Marcellus, enters with Horatio, Hamlet's best friend. The sentinels inform Horatio that they have seen a ghost that looks like the dead King Hamlet. After hearing from Horatio of the Ghost's appearance, Hamlet resolves to see the Ghost himself. That night, the Ghost appears again. It leads Hamlet to a secluded place, claims that it is the actual spirit of his father, and discloses that he—the elder Hamlet—was murdered by his brother Claudius pouring poison in his ear... (Summary by Wikipedia)