Immediately after Hamlet exits, dragging Polonius’ body, we see Claudius asking Gertrude to explain what has happened. She tells him of Hamlet’s accidental killing of Polonius and Claudius realizes that he could have just as easily been slain. Claudius asks where Hamlet has gone and Gertrude says that he has taken the body away. The king orders Rosencrantz and Guildenstern to find Hamlet and discover where he has taken Polonius’ corpse.
Rosencrantz and Guildenstern question Hamlet about Polonius’ whereabouts. Hamlet evades their questions playfully, accusing his former friends of sycophancy to the king and leading them on a wild goose chase.
Claudius is greatly distracted by the death of Polonius and the attempt to find the body. Rosencrantz and Guildenstern enter with Hamlet. Claudius questions Hamlet as to where he has taken Polonius. After some morbidly humorous replies, Hamlet reveals that he hid Polonius “up the stairs into the lobby.” The king sends attendants to find the body. Claudius then tells Hamlet that he is to depart immediately for England, as planned. Hamlet mockingly departs, leaving Claudius to reflect on his plans for Hamlet. He has prepared letters asking the English king, whom Denmark has recently defeated in war, to kill Hamlet as part of the duties owed by right of conquest.
Next we see Fortinbras’ Norwegian army. They are at the borders of Denmark. Fortinbras sends one of his captains to the court of Claudius to ask permission to cross Denmark in the course of their march to Poland. The captain travels on and Fortinbras and the rest of the army exit.
The captain meets with Hamlet, who is being conveyed by Rosencrantz and Guildenstern to the ship to England. Hamlet asks the captain about his army and his purpose in going to Poland. The captain says that in Poland there is “a little patch of ground” which Norway claims as her own. He describes this land as perfectly worthless and small. Hamlet suggests that the Poles will not likely defend such a piece of land, but the captain sets him straight, saying that Poland is already garrisoned and ready for their dispute. Hamlet wraps up his conversation with the captain. He hangs back from the others marching to the ship and delivers a long soliloquy on the irony of this occasion – these men are off to risk their lives for a worthless piece of land, while he, who has every reason to risk his life in the cause of revenge, delays and fails to act. Hamlet resolves to recast his mind to bloody thoughts. Ironically, however, just after making this resolution he continues on toward England, leaving Denmark behind him.
Back in the court of Denmark, we see Gertrude speaking with a gentleman who explains that Ophelia has gone mad. She is rambling nonsensically about her father and insisting on seeing Gertrude. The queen reluctantly admits Ophelia, who proceeds to sing a number of simple and haunting songs, some of them quite bawdy. The king enters and witnesses her madness. Ophelia then speaks openly of her father’s untimely demise and hasty, unofficial burial. She threatens, “My brother shall know of it,” and exits. Claudius reflects on the difficulty of their situation, admitting that their decision to cover up Hamlet’s deed and bury Polonius so covertly has gone against them. He says that Laertes has come from France, egged on by people who see the court as responsible for Polonius’ death.
On cue, a messenger arrives with word that Laertes has come to court with a mob of followers who wish to depose Claudius and make Laertes king. Laertes bursts in and tells his followers to wait outside. In a half-crazed state he insists that Claudius give him Polonius. Claudius attempts to calm Laertes and tells Gertrude to keep out of their talk and let Laertes question him to his heart’s content. Claudius tells Laertes that Polonius is dead. He also insinuates that he and Laertes are on the same side – that he has been injured by Polonius’ death too.
Just as Claudius is about to explain what he means, Ophelia enters again, bearing a bundle of flowers. The sight of his insane sister deeply grieves Laertes. Ophelia handles all those present gifts of flowers, each symbolizing a reproach to the receiver. She sings another song about her dead father and exits abruptly. As she leaves Claudius tells Laertes to inquire into the matter as deeply as he wishes, confident that he will find himself aligned with Claudius against Hamlet. Laertes agrees.
A messenger approaches Horatio, saying that some sailors have news for him. Horatio receives from these sailors a letter from Hamlet. He reads the letter aloud. It recounts an amazing turn of events: on his way to England, pirates attacked Hamlet’s ship. During the fray, Hamlet boarded the pirate vessel. The two ships parted with Hamlet still aboard. The pirates treated Hamlet “like thieves of mercy,” promising to return Hamlet to Denmark in return for some favors. Hamlet also alludes to a startling development having to do with Rosencrantz and Guildenstern but says that he must delay telling of this until they meet. He tells Horatio to follow the sailors to where he is hiding. Horatio says that he will help to deliver the rest of their letters, one of which is addressed to the king, and then go with them to see Hamlet.
Claudius and Laertes are in conference. The king seems to have explained the strange occasion of Polonius’ death to Laertes’ satisfaction. He says that he did not try Hamlet for two reasons, first, because his mother loves him so much, and second, because the people of Denmark are supporters of Hamlet. A messenger arrives and delivers a letter to Claudius, who is greatly surprised to learn that the letter comes from Hamlet. The letter announces Hamlet’s imminent return to court.
With this in mind, Claudius and Laertes plot to find a means of killing Hamlet without upsetting Gertrude or the people. They propose to arrange a duel between Hamlet and Laertes, both of whom are accomplished swordsmen, though Laertes is the more reputed. Claudius suggests that Laertes be given a sharp sword while Hamlet’s remains blunt. Laertes does him one better, saying that he will dip his sword in poison so that the least scratch will kill Hamlet. Claudius says that on top of this he will prepare a poisoned cup and give it to Hamlet during the fight.
Gertrude enters with yet more tragic news. She says that Ophelia has drowned. She was watching Ophelia play in the branches of a willow by the water when she fell in. Gertrude says that Ophelia seemed ignorant of danger and went to her death slowly, singing songs. This news reignites Laertes’ rage and Claudius goes to console him.
You can see simply from the quickness with which the scenes of Act Four proceed that the action has reached a point of great tension following the death of Polonius. We see more evidence of Claudius’ lack of political talent when we learn that he has simply hushed up Polonius’ death, burying his longtime advisor without pomp or circumstance, and keeping the nature of the death a mystery. This, as much as the death itself, prompts the two events most central to Act Four, the return of Laertes and the madness of Ophelia.
First, though, it’s necessary to note that the fourth scene contains another of Hamlet’s famous soliloquies – “How all occasions do inform against me.” This speech reiterates, basically, the point that Hamlet made in his previous soliloquy about the actor playing Hecuba. The basic position of Hamlet is one of befuddlement that these soldiers can go off to their deaths over a patch of worthless ground while he, who has every reason to rage and war and battle Claudius, is introspective and melancholy, and chokes off his action with excessive contemplation. He remarks, “Rightly to be great / Is not to stir without great argument, / But greatly to find quarrel in a straw / When honor’s at the stake.” In other words, the greatness of man comes not with the greatness of an occasion, but with treating any occasion, however petty, as an occasion for greatness. One should not overthink, but do. Of course, this is not Hamlet’s character at all, and as soon as he has resolved that his thoughts be bloody or be nothing worth, he is off to England, leaving revenge for another day, if ever. Indeed, Hamlet seems to express the central irony in his case – it is not enough that his thoughts be bloody. They already are bloody. What he needs, or what his father’s spirit needs, is bloody deeds, not thoughts, and those are, as ever, beyond our protagonist.
Laertes, though, provides precisely the model of what Hamlet is not. The early twentieth century critic A.C. Bradley once illustrated Shakespeare’s gift for characterization by observing that if Othello were in Hamlet’s place the play would be about thirty minutes long – as soon as he learned of the murder, he would kill Claudius – and likewise if Hamlet were in Othello’s he would immediately see through Iago’s plottings and simply laugh the intrigue away. Just so, Laertes’ vengeful return, like Fortinbras’ military example, serves as a contrast to Hamlet’s own hesitating, over-thinking character. This is a true avenger. When he bursts into court demanding satisfaction, he says, “That drop of blood that’s calm proclaims me bastard, / Cries cuckold to my father, brands the harlot / Even here between the chaste unsmirched brow / Of my true mother.” In other words, Laertes proclaims that he has a blood-bound duty to avenge his father’s death impetuously and bloodily, or else he proves himself not his father’s son. In contrast, Hamlet has been calm, reflective, passive, playful, morbid, and impotent in his own long-delayed quest for revenge – a quest which has led rather to an attempt to find motivation to revenge, to reflect on the nature of revenge, the nature of man, and the nature of Hamlet. In short, Hamlet has thought and thought but has not acted. Laertes, we will see, acts without thinking.
The other major event of this Act is the madness of Ophelia. We have seen Ophelia, up to this point, represented as a chaste, innocent, obedient, bewildered little girl. With her madness, however, she suddenly has a deluge of lines and a rich, multi-layered, startling consciousness. The songs she sings are quite sexual – especially the one that begins, “To-morrow is Saint Valentine’s day.” This ballad, which documents the duplicity of a man who promises to marry a young maid in order to get her into bed, and then abandons her because she relented to him, has been read by some as evidence that Ophelia herself gave up her virginity to Hamlet, who then left her in the lurch. In Kenneth Branagh’s adaptation of Hamlet, for instance, the filmmaker explicitly shows flashbacks to Hamlet and Ophelia in bed.
However, it may not be necessary to read the song, and the other songs, so straightforwardly. In her mad scenes, Ophelia is perhaps demonstrating the cultural pressures of a young woman of her time, forced into the impossible position of simultaneous chastity and sexualization. Ophelia, throughout the play, is forever urged to be chaste, be chaste, be chaste – as in Laertes’ instructions, or the “get thee to a nunnery” scene – as a means of controlling her sexual identity. This emphasis on chastity contains, of course, the other side of the coin, a concern with lewdness. She must know nothing about sex, yet know enough to avoid it. In her madness, it seems as though Ophelia’s inner dam, so to speak, has broken, and all of her contained knowledge of sexuality, and of the unfair position of women within her culture, has come rushing out.
Ophelia’s death by drowning is one of the famously impossible-to-settle questions of Hamlet. Did she die accidentally or did she commit suicide? If one looks forward to Act Five, it seems as though she was indeed a suicide. Given the immediate evidence of Gertrude’s testimony, however, there is no reason at all to believe that she killed herself. Gertrude describes her as dying almost in slow motion: “Her clothes spread wide, / And mermaid-like awhile they bore her up, / Which time she chanted snatches of old lauds, / As one incapable of her own distress, / Or like a creature native and indued / Unto that element.” Indeed, the question to ask given this description is not, “Did Ophelia kill herself?” but rather, “If she had time to sing songs while dying, why on earth didn’t Gertrude try to save her?” Perhaps, though (as suggested in the television series, Slings & Arrows, among other places), Gertrude's narrative is an attempt to protect Ophelia. She knows that Ophelia is better off dead and tries to hide the fact of her suicide with her narrative. As with so many aspects of this play, the truth is not forthcoming.
These shifts in meaning from Act to Act are difficult to pin down, but they serve to underline one of the most prevalent trends in the play, toward interpretive uncertainty. Any account of things in this play – whether the testimony of the ghost, the murmurings of Laertes’ followers, or this eye-witness account of Gertrude’s – leads to quite divergent interpretations. As Hamlet says in Act Two, “[T]here is nothing either good or bad, but thinking makes it so.” If there is one lesson to take from Hamlet, it is this – that by our very nature we cannot ever know the truth, only interpretations of the truth.