In June 2003 Belgian authorities arrest Michel Fourniret for attempted kidnapping and assault. After linking him to two other cases, they begin interrogating his wife Monique.
A prosecutor recalls Olivier and Fourniret's sheer lack of empathy as they uncovered the bodies of young women they are suspected of murdering. Later, the circumstances behind how Fourniret could afford a chateau is called into question.
When the trial opens, Olivier's role as a mother spikes public fascination and hatred. As the couple's crimes come to light, so does their sadistic sex life.