For the first time in the play, M. Anselme shows up. Remember him? He's the guy that Harpagon wants to marry his daughter Élise.
Harpagon tells Anselme that he (Anselme) has been robbed of a bride just like Harpagon has been robbed of his money.
Anselme, who is apparantly a way nicer guy than Harpagon, says he has no interest in forcing someone to marry him. Élise can do what she likes as far as he cares.
Harpagon again orders the police officer to arrest Valère. But Valère insists again that once everyone knows who he is, they'll stand down.
Harpagon thinks he's making all of this up, but Valère assures the room that he is a man of noble descent from Naples, Italy.
M. Anselme warns Valère not to lie. He knows everyone in Naples and will know if Valère is telling the truth.
Valère pops on a fancy looking hat and claims that he is the son of a man named Don Thomas D'Alburci. M. Anselme accuses him of lying, since he claims to know Don Thomas well.
It's impossible, says M. Anselme, since Don Thomas died sixteen years ago in a shipwreck, along with his wife and children.
Valère says that a servant saved him from the ocean and they were picked up by a Spanish ship sailing nearby. The captain of this ship then raised Valère as his own.
Valère later heard that his father wasn't in fact dead, and he tried to track him down. But he got sidetracked in his search when he fell in love with Élise.
M. Anselme isn't convinced, and wants more proof. Valère offers the testimony of the Spanish captain who raised him, as well as a ruby seal that belonged to Don Thomas and an agate bracelet that his mother gave him.
At this point, Mariane, who has quietly walked onstage, cries out that Valère must be her brother! It turns out that she and her mother also made it out of the shipwreck. They returned to Italy with no estate and have been living a life of poverty ever since.
When Mariane is finished, M. Anselme also cries out for joy and calls Valère and Mariane his children. It turns out that he is none other than Don Thomas D'Alburci. And yes, he survived the shipwreck, too. He changed his name and started a new life in order to get over the loss of his family.
When Harpagon finds out that Valère is M. Anselme's son, he demands that M. Anselme pay him the money that Valère has stolen.
Valère demands to know who said he took the money. When he finds out, he looks like he's going to give Master Jacques another good beat-down.