Something is rotten in the state of Denmark. Two night-watchmen at the castle at Elsinore have seen a ghost they believe to be the former king of Denmark, the father of Prince Hamlet. The soldiers entreat Horatio, Hamlet's confidant, to wait with them for the ghost's appearance during the night watch. Horatio is horrified by its resemblance to the dead king. The men ask Hamlet to join the watch, and when the ghost appears, it reveals to Hamlet that he is, indeed, the spirit of his father. Then his father's ghost informs Hamlet that he was murdered by Claudius, the current king of Denmark.
Claudius, Hamlet's uncle and brother of the former king, has not only usurped the throne of Denmark through foul murder, but has also taken Gertrude, Hamlet's mother, as his wife. Hamlet vows to avenge the death of his father and says he will put on an "antic disposition" to distract others from his genuine purpose.
Hamlet's indecision and his madness—feigned or real—will result in tragedy for himself and all those around him.
The Folger Shakespeare Library edition includes useful contextual glossaries, providing definitions, historical notes, and additional information to help understand the language of Shakespeare as you read.