It is the biggest unsolved serial murder case in British criminal history - the so-called 'Jack the Stripper' murders took place in Swinging Sixties London. Professor Wilson and his investigative team - which includes former detective Jackie Malton and forensic psychologist Professor Mike Berry - begin their hunt for the killer not in London, but 150 miles away in Abertillery, South Wales. In 1921, the Welsh mining town was devastated by the double murder of two schoolgirls when eight-year-old Freda Brunell and 11-year-old Florence Little were killed just weeks apart by a local boy, 15-year-old Harold Jones, who the Abertillery residents still refer to as their 'Dark Son'.