In the 1980s, nearly 20 children vanished into thin air in Switzerland. Some were found dead, having been tortured and sexually assaulted. Others disappeared without a trace. Such was the case of Sylvie Bovet. Then, four months later, of Sarah Oberson, aged 5, who has been missing since September 1985. Two serial killers criss-crossed the country at the time: Michel Peiry, dubbed 'the Sadist Of Romont,' whose sexual crimes were committed between 1981 and 1987. And Werner Ferrari, who murdered five children aged 7 to 12 between 1980 and 1989 after sexually abusing them. These atrocities unveiled a reality beyond imagination,  one of the darkest chapters in Swiss criminal history.

Filming Locations
Orsières, Valais (location where the body of Vincent, a victim of the "Sadist of Romont," was discovered).
Saxon, Valais (the village where Sarah Oberson disappeared in 1985).
Romont, Canton of Fribourg (home of Michel Peiry, serial killer).
Zurich Region (home of Werner Ferrari, serial killer).

Key Contributors
Céline (sister of Vincent, a victim of Michel Peiry murdered in 1987).
Corinne Jacquet (journalist specializing in crime news, publisher at Le Chien jaune publishing house).
Emmanuel Meyer (inspector with the Valais Cantonal Police, investigator on the Sarah Oberson case).
Pierre-Antoine Langen (head of the Valais Judicial Police, who started his career on the Oberson case).
Georges André Lesueur (inspector with the Neuchâtel Cantonal Police, investigator on the Sylvie Bovet case).
Justine (sister of Sarah Oberson).

Key Themes
Disappearance and murders of twenty children in Switzerland during the 1980s by two pedophile serial killers, Michel Peiry and Werner Ferrari.
The limitations of police investigation methods in the 1980s when dealing with serial crimes.
The lasting traumatic impact on the victims' families, and the trauma of living without answers.

Key Figures
1987: Life imprisonment for Michel Peiry for the murders of five young boys.
1995: Life imprisonment for Werner Ferrari for five confirmed child murders.
No answers for the families of Sarah Oberson and Sylvie Bovet, 40 years after their disappearances in 1985.

Quotes
Emmanuel Meyer, inspector: "When we talked to him about the people he assaulted and killed, he explained it from A to Z. Without missing a word, without stuttering, without anything at all."
Justine: "We are no longer here to accuse anyone. The question is simply to know what became of Sarah. That is the question that haunts our minds."