Orgon explains his concern over the strongbox to Cleante - the strongbox was given to him by a friend who had supported the wrong army in the recent wars. The friend's papers were hidden in the box, and his life and safety depended upon their secrecy. Worried he might be interrogated about it, Orgon had asked Tartuffe to hide it. Cleante realizes the direness of the situation, and remarks, "He's holding all the cards, your holy man." Infuriated, Orgon rages against holy men in general, describing them as "filled with deceit!"
Cleante, however, suggests Orgon is too hasty in his generalized judgment. He reminds Orgon that just as not all holy men are trustworthy, neither are they all deceitful. He cautions his brother-in-law to judge men by simple goodness, and not by extreme outward displays of piety.
Damis enters in a fury, threatening to murder Tartuffe. Cleante rebukes him for his rash insistence on pursuing an unlawful course of action.
Madame Pernelle, Elmire, Mariane, and Dorine join the men. Madame Pernelle refuses to believe the report of Tartuffe's betrayal, and claims her son has fallen prey to the "false suspicions" of his family. Everyone tries to convince her to recognize the truth, to no avail.
They discuss how to proceed against Tartuffe, and Cleante muses that the tricky Tartuffe might attempt to trap Orgon in a "legal maze." When there is a knock at the door, Dorine opens it to discover Monsieur Loyal, a seemingly gentle man who claims to carry a message from Tartuffe. When they allow him in, he reveals himself as a bailiff, who conned his way inside so that he can serve them with a "writ from the court," filed by Tartuffe to remove them from the premises.
The family is shocked. Monsieur Loyal, irritatingly placid, explains that because Tartuffe has the deed to the house, the family must vacate it. Damis threatens the man, but Monsieur Loyal is not impressed. With an air of ironic accommodation, he allows the family to remain in the house through the evening so they can pack their belongings. Enraged, Orgon threatens to attack Monsieur Loyal, but Cleante calms him and then shows Monsieur Loyal out.
After Monsieur Loyal leaves, Madame Pernelle realizes the truth about Tartuffe. Elmire suggests that they find a way to prove the hypocrite's trickery, and thereby save their estate.
Valere suddenly bursts into the room with more bad news: Tartuffe has reported Orgon as a traitor to the King, and offered the strongbox as evidence. There is now a warrant for Orgon's arrest, so he must flee immediately. Valere offers to lend Orgon his carriage and ten thousand in gold to expedite the escape. Orgon bids goodbye to his wife, and prepares to leave.
Before he can leave, however, Tartuffe and the Exempt, a police officer, enter the room. Tartuffe mocks Orgon's cowardice, and compliments himself on suffering for Heaven's sake. He informs the family about the serious duty he has performed in reporting Orgon's treachery, and Cleante wonders why he had never fulfilled this "duty" before being banished from the house. Tartuffe then tells the Exempt that he tires of the family's whining, and suggests the Exempt should do his job.
The Exempt agrees, noting that he has confirmed the facts that the King had suspected. However, he prepares to arrest Tartuffe, not Orgon. Tartuffe is aghast. The Exempt explains that Tartuffe will be locked in jail without bail, because the King cannot be easily deceived by fraud. The King saw the "base cowardice" lurking in Tartuffe's heart, and knew of other crimes the man had committed. He merely wanted the facts confirmed before the charlatan was tossed into jail, and thus sent them to the house. The King intends to return the strongbox, and to hold Orgon faultless since he knows Orgon is loyal to him. The Exempt concludes that "a good deed deserves a recompense, / He pardons you."
The family rejoices, and Cleante convinces Orgon not to involve himself in Tartuffe's punishment. He suggests it is better that Orgon does not stoop to his level. Orgon agrees, and then announces his intention to prepare a wedding for Mariane and Valere.
Act V concludes the play, and it seems that all is right with the world. Tartuffe has been unmasked and appropriately punished. Damis has returned, and is forgiven. Mariane is allowed to marry Valere. Orgon has more or less recovered his right mind. Madame Pernelle has had to confront her erroneous opinions. Cleante has convinced Orgon not to assume that all religious men are frauds. The king has forgiven Orgon for his questionable involvement with the strongbox, and the house has been returned to the family. The play, then, ends on a happy note, in keeping with the basic structure and purpose of classical comedy. However, some critics and readers/audiences have found Orgon's abrupt rescue a little too pat, and there are several unresolved mysteries and questions that linger after the curtain falls (or the book closes).
For instance, mysteries surround Tartuffe. The character's origins and background remain unknown, which makes him seem an almost allegorical figure. He simply appears at Orgon's church one day, and ingratiates himself into the household by personifying certain characteristics (piety to Orgon, deceit to all others). The play, as critic Marcel Gutwirth remarks, "refuses to make up its mind" about its titular character. He seems a glutton in the second act, a jailbird in the fifth, and deviates between being a religious hypocrite and a confidence man, or a nobleman and a penniless fraud. The few things know for certain are that, in Gutwirth's words, "he does lay claim to a very special relation to heaven; and, though far less overtly, sex exercises an equally strong claim on his person." Tartuffe weaves a mystery about himself that is so complete that it is possible to wonder if he believed some of it himself. Interestingly, he continues to spin his web of deceit even after he already ostensibly won, claiming he betrayed Orgon simply from duty. He is central to the plot but hardly the character we know most about, suggesting that the play is titled after him because of what he represents, and not because his personality defines it.
Another mystery is why the family so quickly forgives Orgon his rotten behavior. This parallels the speed with which Orgon becomes a sane, rational person after seeing the truth of Tartuffe's deceit. The answer to this charge again lies in Moliere's interests - he seems not to have aimed for psychological detail but rather for the way stock characteristics can relate to us all. To have sculpted realistic changes-of-heart would certainly have required more dialogue and nuance than a madcap comedy supports. What's important is that we accept the change, not that we observe the realistic way in which such changes happen.
The king serves in the play is a deus ex machina, a literary device most often connected to Greek drama. In effect, a deus ex machina is something or someone who appears with a sudden solution to complicated, seemingly-impossible situations. The play seems headed for tragedy when a sudden word from the Exempt rectifies all troubles. Realistically, Orgon would likely pay penance for his gullibility and rash decisions, but the King's beneficence restores all to order.
There are reasons to think Moliere was attempting to praise his king, Louis XIV, through the play. Obviously, the King is represented as a model of kindness and shrewdness. Little detail is given to explain how he recognized Moliere's deceit so quickly, for instance. Further, Orgon is not saved entirely in spite of himself. As noted in Act I, he had recently proved his loyalty by supporting the King in a war. Thus, Louis is implicitly praised for his grace towards supporters. Considering that Louis was a great supporter of Moliere, it is not unlikely that the playwright felt compelled to praise him, though it does rankle some critics. One literary critic wrote in 1930 that this ending was basically a "politic proclamation of the King's favour and support," which is "an excrescence upon the comedy." More modern interpretations suggest that the sudden ending is not uncommon for comedies, and hence is not improper.
Regardless, by the ending, the audience has come to understand Moliere's views on religion. He does not mean to rail against religion in itself, but rather despises the hypocrisy that religion allows deceitful men to evince. Moliere does not approve the religion of Tartuffe, Orgon, or Madame Pernelle, all of whom use strong emotional reactions to justify their faith. Instead, he supports the religion of Cleante, which lauds men who "speak of their mortality," instead of their morality. They "don't form cabals, they don't have factions, / They don't censure other people's actions. They see the flagrant pride in such correction / And know that humans can't achieve perfection." Simply put, Moliere supports an honest religion, one that embraces man's limitations rather than ignoring them.
What is so ironic about the history of Tartuffe is that religious men of Moliere's day criticized the work, and encouraged its reputation as diatribe against religion even as it proffers such a positive support of true piety. This perverse misunderstanding might be the biggest mystery of all.