what happens in act 4 of the tempest?

Question

i cant find my book. im not cheating, i swear.

or if you know a site where i could read it that would help too.

Answer 1

Sparknotes can help:

"Act IV, scene i
Summary
Prospero gives his blessing to Ferdinand and Miranda, warning Ferdinand only that he take care not to break Miranda’s “virgin-knot” before the wedding has been solemnized (IV.i.15–17). Ferdinand promises to comply. Prospero then calls in Ariel and asks him to summon spirits to perform a masque for Ferdinand and Miranda. Soon, three spirits appear in the shapes of the mythological figures of Iris (Juno’s messenger and the goddess of the rainbow), Juno (queen of the gods), and Ceres (goddess of agriculture). This trio performs a masque celebrating the lovers’ engagement. First, Iris enters and asks Ceres to appear at Juno’s wish, to celebrate “a contract of true love.” Ceres appears, and then Juno enters. Juno and Ceres together bless the couple, with Juno wishing them honor and riches, and Ceres wishing them natural prosperity and plenty. The spectacle awes Ferdinand and he says that he would like to live on the island forever, with Prospero as his father and Miranda as his wife. Juno and Ceres send Iris to fetch some nymphs and reapers to perform a country dance. Just as this dance begins, however, Prospero startles suddenly and then sends the spirits away. Prospero, who had forgotten about Caliban’s plot against him, suddenly remembers that the hour nearly has come for Caliban and the conspirators to make their attempt on his life.
Our revels now are ended. These our actors,
As I foretold you, were all spirits, and
Are melted into air, into thin air;
And, like the baseless fabric of this vision,
The cloud-capped towers, the gorgeous palaces,
The solemn temples, the great globe itself,
Yea, all which it inherit, shall dissolve;
And, like this insubstantial pageant faded,
Leave not a rack behind. We are such stuff
As dreams are made on, and our little life
Is rounded with a sleep. (IV.i.148–158)

Prospero’s apparent anger alarms Ferdinand and Miranda, but Prospero assures the young couple that his consternation is largely a result of his age; he says that a walk will soothe him. Prospero makes a short speech about the masque, saying that the world itself is as insubstantial as a play, and that human beings are “such stuff / As dreams are made on.” Ferdinand and Miranda leave Prospero to himself, and the old enchanter immediately summons Ariel, who seems to have made a mistake by not reminding Prospero of Caliban’s plot before the beginning of the masque. Prospero now asks Ariel to tell him again what the three conspirators are up to, and Ariel tells him of the men’s drunken scheme to steal Prospero’s book and kill him. Ariel reports that he used his music to lead these men through rough and prickly briars and then into a filthy pond. Prospero thanks his trusty spirit, and the two set a trap for the three would-be assassins.
On a clothesline in Prospero’s cell, Prospero and Ariel hang an array of fine apparel for the men to attempt to steal, after which they render themselves invisible. Caliban, Trinculo, and Stefano enter, wet from the filthy pond. The fine clothing immediately distracts Stefano and Trinculo. They want to steal it, despite the protests of Caliban, who wants to stick to the plan and kill Prospero. Stefano and Trinculo ignore him. Soon after they touch the clothing, there is “A noise of hunters” (IV.i.251, stage direction). A pack of spirits in the shape of hounds, set on by Ariel and Prospero, drives the thieves out.
Analysis
The wedding of Ferdinand and Miranda draws near. Thus, Act IV, scene i explores marriage from several different angles. Prospero and Ferdinand’s surprisingly coarse discussion of Miranda’s virginity at the beginning of the scene serves to emphasize the disparity in knowledge and experience between Miranda and her future husband. Prospero has kept his daughter extremely innocent. As a result, Ferdinand’s vulgar description of the pleasures of the wedding-bed reminds the audience (and probably Prospero as well) that the end of Miranda’s innocence is now imminent. Her wedding-night will come, she will lose her virginity, and she will be in some way changed. This discussion is a blunt reminder that change is inevitable and that Miranda will soon give herself, in an entirely new way, to a man besides her father. Though Prospero somewhat perfunctorily initiates and participates in the sexual discussion, he also seems to be affected by it. In the later parts of the scene, he makes unprecedented comments on the transitory nature of life and on his own old age. Very likely, the prospect of Miranda’s marriage and growing up calls these ideas to his mind.
After the discussion of sexuality, Prospero introduces the masque, which moves the exploration of marriage to the somewhat more comfortable realms of society and family. In the sixteenth and seventeenth centuries, masques were popular forms of entertainment in England. Masques featured masked actors performing allegorical, often highly ritualized stories drawn from mythology and folklore. Prospero’s masque features Juno, the symbol of marriage and family life in Roman mythology, and Ceres, the symbol of agriculture, and thus of nature, growth, prosperity, and rebirth, all notions intimately connected to marriage. The united blessing of the union by Juno and Ceres is a blessing on the couple that wishes them prosperity and wealth while explicitly tying their marriage to notions of social propriety (Juno wishes them “honor”) and harmony with the Earth. In this way, marriage is subtly glorified as both the foundation of society and as part of the natural order of things, given the accord between marriage and nature in Ceres’ speech.
Interestingly, Juno and Ceres de-emphasize the role of love, personal feeling, and sexuality in marriage, choosing instead to focus on marriage’s place in the social and natural orders. When Ceres wonders to Iris where Venus and Cupid, the deities of love and sex, are, she says that she hopes not to see them because their lustful powers caused Pluto, god of the underworld, to kidnap Persephone, Ceres’s daughter (IV.i.86–91). Iris assures Ceres that Venus and Cupid are nowhere in sight. Venus and Cupid had hoped to foil the purity of the impending union, “but in vain” (IV.i.97). Ceres, Juno, and Iris have kept the gods of lust at bay; it seems that, through his masque, Prospero is trying to suppress entirely the lasciviousness of Ferdinand’s tone when he discusses Miranda’s virginity.

In almost all of Shakespeare’s comedies, marriage is used as a symbol of a harmonious and healthy social order. In these plays, misunderstandings erupt, conflicts break out, and at the end, love triumphs and marriage sets everything right. The Tempest, a romance, is not exactly a comedy. However, it is deeply concerned with the social order, both in terms of the explicit conflict of the play (Prospero’s struggle to regain his place as duke) and in terms of the play’s constant exploration of the master-servant dynamic, especially when the dynamic appears unsettled or discordant. One reason Shakespeare might shift the focus of the play to marriage at this point is to prepare the audience for the mending of the disrupted social order that takes place at the end of the story. Calling upon all the social and dramatic associations of marriage, and underscoring them heavily with the solemnity of the masque, Shakespeare creates a sense that, even though the play’s major conflict is still unresolved, the world of the play is beginning to heal itself. What is interesting about this technique is that the sense of healing has little to do with anything intrinsic to the characters themselves. Throughout this scene, Ferdinand seems unduly coarse, Miranda merely a threatened innocent, and Prospero somewhat weary and sad. But the fact of marriage itself, as it is presented in the masque, is enough to settle the turbulent waters of the story.
After this detailed exploration of marriage, the culmination of Caliban’s plot against Prospero occurs merely as a moment of comic relief, exposing the weaknesses of Stefano and Trinculo and giving the conspirators their just deserts. Any hint of sympathy we may have had for Caliban earlier in the play has vanished, partly because Caliban’s behavior has been vicious and degraded, but also because Prospero has become more appealing. Prospero has come to seem more fully human because of his poignant feelings for his daughter and his discussion of his old age. As a result, he is far easier to identify with than he was in the first Act. Simply by accenting aspects of character we have already seen, namely Prospero’s love for Miranda and the conspirators’ absurd incompetence, Shakespeare substantially rehabilitates Prospero in the eyes of the audience. We can cheer wholeheartedly for Prospero in his humorous defeat of Caliban now; this is one of the first really uncomplicated moments in the play. After this moment, Prospero becomes easier to sympathize with as the rest of the story unfolds."

or Cliff Notes - see link 2, please.