The first case in the programme looks at the Belgian poisoner Marie Becker, who during the 1930s carried out a series of poisonings, killing eleven people in total. Becker, who lived in the historic city of Liege, used digitalis, an extract from the foxglove plant, and administered it into cups of tea and glasses of wine. Her victims were mainly elderly ladies whom she would befriend in coffee shops and whose trust she would rapidly gain.