The killer breaks into her home and kills her, before catching a glimpse of the woman's daughter, Ines, in a photograph before leaving.

Elsewhere, Giulia Torresi is picking a dress for her marriage to Mario, a wealthy clothing designer, when she receives a mysterious call, who hangs up when asked their identity.

While the police suspect Mario, Giulia recognizes one of the previous victims as a fellow employee at the hotel she formerly worked at.

Once free from recovery, Giulia second guesses herself and confesses to Mario that she thinks she's accused the wrong man.

In the car, she notices that Mario suspiciously has the exact half moon plaque left behind at each murder scene.

Giulia subsequently remembers a vague memory of a frequent guest at her hotel who shared a similar half moon on their key chain.

Whilst driving back however, she remembers that the names of the previous guests must be legally kept in an official hotel register.

What is present is a list of women: Anita Ferri, Kathy Adams, Elena Marchi, Concetta de Rosa, Anna Sartori, as well as Ines and Giulia who had worked at the hotel.

After not being able to relax and have a proper honeymoon, Mario and Giulia return to Italy to carry out their own investigation, starting with paying the third woman on the list a visit.

An odd circumstance comes up when the parish priest, briefly seen during Mario's investigation, informs the police that the teacher, Concetta de Rosa, had not attended church as usual.

After going to the address stated, Mario finds out that his suspect, Frank Saunders, had died in an automobile accident two years prior.

Anna Sartori, a name not explored much on the list, arrives in Italy only to be immediately confronted by the police.

Anna's husband explains she experienced a traumatic event of sorts while briefly living in Italy.

Anna, not able to do practically anything to ensure her safety, sends her identical twin sister, Maria, out to get the newspaper for her.

At this point, Giulia is sick of hiding out and hatches a plan to catch the murderer by announcing her state to the public.

He explains that the killings were sparked out of the fact that one of the many women on the list had to have been the one to abandon his brother and leave him to die in the car accident.