Giulia is a 22-year-old girl who studies medicine in Florence but is from Arezzo where she returns to her family every Friday evening by train. On one of these trips she meets Alessandro alarm systems technician who is from Rome but works in Florence for a security company. A mutual interest erupts between the two which will lead to an unexpected epilogue. In fact, after some hesitation, the girl accepts Alessandro's courtship, leaving before her her boyfriend Lorenzo with whom she had been together for 5 years. Passion breaks out between the two but the morning after the night they spent together the police show up at the door of the hotel where Alessandro is staying, accusing the boy of robbery and murder. The girl is immediately exonerated but Alessandro remains in prison pending the investigations that Giulia will carry out in part without the knowledge of her parents. In fact, the girl digs into the boy's past even going to his family in Rome.