The mouse is still an issue at Camilla's house. At police headquarters, Berardi has his hands full with the mother of the murdered detective and Mattioli's wife.

Ottavia and Palma talk about his new apartment and the fact that it is still empty. Lojacono gets some good news from his friend Paolo and shares it with Marinella. He goes to the train station to wait for Laura and gets an idea about the case.

This episode is about a specialty from Colonnata, a little village above Carrara, where marble is quarried. It's pork lard, which may not sound very appetizing but is beloved by Italians all over the peninsula. A little goes a long way, but savored with typical unsalted Tuscan bread, it is pretty special. And marble plays an important part.

Melania Gaia Mazzucco talks about one of her novels set in seventeenth-century Trastevere, quite a different place than what we see today. Although she has traveled the world, Mazzucco comes from generations of romani di Roma (Romans from Rome).

Camilla, in conversation with her mother, hopes that the postcard from New York is just a misunderstanding. Renzo has a moment of truth by a dumpster. Later, he says something about Dr. Mattioli that gives Camilla an idea about her "hallucinations."

Lojacono is not at all convinced that Varricchio killed his own children, especially after talking to him. Pisanelli got some bad news about another retiree having taken his own life. Pisanelli had been watching over the wrong home.

This is the story of an Italian, who haveing been brought up on a dairy farm, travels the world, ending up in Australia, only to return to Italy with some new ideas about the cheese he wants to create.

Armando talks about how the works of Duchamp influenced his work and that of so many contemporary artists. The choice of a unique exhibition hall played a part, as well.

Annalena continues talking with Paolo Giordano, who talks about how places such as Afghanistan and Apulia have influenced his writing.

Camilla can't help herself and goes to the home of Mattioli's former nurse. Gaetano leaves Camilla a text message. Note that in Italy, texting while driving is now prohibited.

Lojacono follows Varricchio to his hotel to ask a few more questions, in private.

The bread from Altamura (in Apulia) is very famous among Italian bread connoisseurs. Beppe di Gesù, our host in this segment, comes from a long line of bakers. Breadmaking is so special that it's called l'arte bianca (the white art), because of the color of the flour.

Not only are Armando's photographs reminiscent of the universe and nature — they also recall other works of art from history.

Annalena meets up with Paolo Giordano who talks about the trauma of moving from Turin to Rome. Giordano's first novel, La solitudine dei numeri primi (the solitude of prime numbers) from 2008 was made into a popular film of the same name in 2010.

Camilla is still convinced there is a mouse in the house and Renzo humors her. At school, there is some tension, but Marchesi has some information for Camilla and her mood changes. Berardi also obtains, almost by accident, some intriguing information, that could be pertinent to the case.