Franck (Guillaume Canet), is a model policeman; disciplined, conscientious and appreciated by his superiors. When a number of women are brutally murdered, Franck leads the investigation to find the suspected serial killer responsible for the crimes. However, all police efforts seem to be in vain as the alleged 'maniac' continues to evade capture. That is, until Franck loses his private collection of maps, detailing the locations of the missing bodies. Film recalls the true story of Alain Lamare, the infamous serial killer whose rampage terrorised France in the late 1970's, and the nationwide manhunt to find him.