Back on the parapet — the outer walls of Castle Elsinore — Hamlet follows the Ghost, who admits that he is the spirit of King Hamlet and tells his son to hear him out. His time is short before he must return to Purgatory. He cannot share any of the secrets of life in Purgatory, but he has a tale of woe he desperately needs to pass on to his son. Before he will give Hamlet any details, however, he charges the Prince to avenge his murder. The words of the Ghost horrify Hamlet, for they confirm his fears. Hurrying because he can "scent the morning," King Hamlet tells his son that Claudius seduced his seemingly virtuous queen, and then crept to where his brother lay napping and poured a lethal poison in King Hamlet's ear. The poison quickly curdled King Hamlet's blood, robbing him of both his life and the opportunity for absolution.
The Ghost tells Hamlet to "Remember me," but only after he instructs him to leave Gertrude alone. So Hamlet must wrest retribution only from Claudius. The Ghost exits, leaving Hamlet incensed. Hamlet answers the worried calls of Horatio and Marcellus, telling them nothing specific but demanding that they both take an oath to tell no one what they have seen and heard. In confidence, Hamlet tells Horatio that he will pretend to be mad so that he may spy on his mother and uncle. After Horatio has sworn allegiance, Hamlet bids the departed Ghost to rest and then curses his fate before exiting with the other men.
