During questioning, the passengers seem to agree about one person getting back on the bus during the rest stop: Luca's sister. Buttafuoco and Barbagallo finish up checking the luggage, but they come across an extra bag.

There's a problem at school, and of course, our Prof (short for professore [professor, teacher], the affectionate, abbreviated term students use in addressing a teacher) has to investigate.

Christmas dinner is interrupted by a phone call from the plant, where engineers are working. Karen listens in. She then has an ominous meeting with the Americans.

The contents of the blue backpack point to a possible motive. Luca talks to his sister again, but she is still visibly upset, which is understandable. Marta finally talks to Luca about what has been weighing on her for a while.

The protest at school continues, and there is tension among the teachers and the principal. At home, Renzo has a first encounter with the housekeeper. He finds her a bit odd.

Karen sends a clear message to Adriano and they meet. She has something important to tell him.

Luca goes to see Ginevra about the autopsy, but he confides in her, too. Toscani is having trouble telling Luca the results of his investigation into the passengers of the bus.

Little Livia is in the backseat as her mom drives another teacher home. She listens, she opens her mouth when she shouldn't, she observes. She draws her conclusions and then bets on them with her mom.

Mauro gets a political slap in the face. Olivetti is undergoing huge financial challenges and risks going under but Adriano doesn't lose hope.

Luca is very upset with his sister. He feels betrayed and starts getting really worried, both for her and for himself, since he has gone out on a limb for her. The investigation continues.

Bettina has tea with Camilla and invites her to a gallery event. Camilla then gets a phone call that requires her attention and she rushes off.

Adriano is on his way to Switzerland. Before he gets on the train, he exchanges a solemn few words with someone who used to be a friend.

Marta is very convincing in her role as a sexy dancer at the night club, maybe too convincing. The situation takes a darker turn and she gets more and more concerned.

Camilla really is a good friend to Vanda. Vanda, on the other hand, is a bit naive. They have a heart-to-heart talk.

If the name Olivetti is still known today, it's because Adriano Olivetti made an important contribution to the industry of electronics, but also to the ethics of industry in general.