"He was attractive, cultivated, very sensitive, very empathetic". Lawyer Astrid Wagner's first impression when meeting the serial killer Jack Unterweger. As a young law student she had close contact with him: "It was a nice feeling to be needed." On June 28, 1994 Unterweger is convicted for the murder of nine prostitutes. Six hours later, he hangs himself in his cell. Twenty years later, Thema unrolls the incredible story of the woman murderer and asks former friends and other companions how Jack Unterweger influenced their lives.

The story of Austrian, Johann "Jack" Unterweger (1950-1994), who wrote a book about his criminal past while serving a life term in prison for assault. In 1974, Unterweger murdered 18-year-old German citizen Margaret Schäfer by strangling her with her own bra, and in 1976 was arrested and sentenced to life in prison. And that was only the beginning... Epsidode 1:4 of "Serial Killers".