Marcuccio has gotten hungry, and so he's gone to see the only person he could trust, Lara's zia Caterina. But by the time anyone could come to help her, he'd disappeared again, leaving his jacket behind. Lara's dog, Brigadiere, gets a good whiff and goes off with Luca to look for Marcuccio. A storm has come up, making things more difficult.

Lara and Luca go to interrogate a suspect whose only alibi for the night of the murder depends on Marcuccio, who is still missing. Meanwhile, Giulia intercepts a cryptic phone call.

Amidst murder and insomnia, Manara is attempting to eat his croissant during the autopsy in the morgue. And Ginevra... well, she has an infallible solution to help him get back to normal.

The police intercept a phone call between Marcuccio and his mother, but it's too short to trace. Marcuccio recites the first line of Leopardi's most famous poem, "L'infinito" [The Infinite] to his mother. Giulia spends the night at Lara's and they watch the movie of the famous party. The next day Lara has some interesting news for Manara, from both Giulia and from her aunt!

Lara and Giulia have some catching up to do, but how candid are they being with each other? Do we detect a bit of jealousy? Meanwhile Commissioner Manara has to deal with both Romei, the chicken guy, and his buxom, brassy wife, who keeps trying to catch Luca's eye.

The arrival of Giulia Chiamparini, the expert in Cultural Heritage, makes quite a hit at headquarters!

Manara goes to see the mother of Fazi's missing assistant, Marcuccio. It turns out he's "different" but with a phenomenal capacity for numbers. He's also a big guy, with big feet! Meanwhile, Lara and Luca are called to their boss's office. He wants results, fast, and so he's called in an expert in Cultural Assets from Rome to work alongside them.

Murder in the library. The curator of the town library was found dead by his secretary, and the assistant librarian hasn't shown up for work. Some valuable correspondence is missing, and there are some suspicious shoe prints on the floor. Manara and his team have gotten busy trying to figure it all out.

Commissioner Manara is back with a new episode, which opens, not only with the usual murder, this time in a library, but also with a care package from Manara's mother, full of Sicilian specialties such as melanzane sottolio or sott'olio, (eggplant in oil). Sottolio is a traditional and well-loved way of preserving many foods, and can be distinguished from sottaceto (in vinegar), or in salamoia (in water and salt). Of course, everyone at headquarters is more interested in the Sicilian pastries!

In the end, Lara decides that Luca Manara isn't such a bad commissioner after all. She might even tell him that to his face... sooner or later.

Although Commissario Manara's has resolved the case, his unorthodox methods are unacceptable to his superior, who threatens to have him transferred to the hinterlands of Sardinia.

At this point the murderer is easily discovered and just as easily confesses. The evening of the murder gets revisited and all previous doubts vanish. But what's to become of the killer?

In the presence of Ginevra who has come to thank both Lara and Manara for saving her reputation, they look once again at the painting of Lorenzo. A detail gives them the key to finding the murderer!

Commissioner Manara and Inspector Rubino figure out who wrote the love letters and Lara conducts the appropriate interrogation.

An important new element in the investigation comes into play: some romantic letters found at the victim's house. Lara is comparing the handwriting to that of the note found next to his dead body.