Scene V opens on another part of the battlements where Hamlet confronts the Ghost, demanding to know where it will lead him. The Ghost identifies itself as the spirit of King Hamlet, condemned to wander until his murder is avenged, and warns that his “hour is almost come” before he is consumed by fire. The Ghost then recounts the foul manner of his death: while sleeping in his orchard he was poisoned, a “serpent” (the poison) poured into his ear, curdling his blood and killing him instantly. He names his murderer as his own brother—now King Claudius—who stole the crown and the queen, committing “incestuous, adulterate” treachery. He orders Hamlet to revenge this “most foul, strange and unnatural” murder but to leave his mother, Queen Gertrude, to heaven’s judgment. Hamlet reacts with outrage, cursing his mother and the “villain” who wears the crown, and pledges to remember the Ghost forever. He declares he will adopt an “antic disposition” (feign madness) to pursue his revenge unnoticed.

Horatio and Marcellus enter off‑stage, asking what has transpired. Hamlet commands them never to speak of what they have witnessed, swearing them on his sword. Both swear, and the Ghost beneath the platform repeats the oath. Hamlet then urges them to keep their hands on his sword and keep the secret, promising they will not be told again. He reflects that “there are more things in heaven and earth than are dreamt of in your philosophy,” and explains that he will put on madness so that his actions can remain hidden. The scene ends as Hamlet, Horatio, and Marcellus prepare to leave together, bound by the oath and the Ghost’s command.